Beaconing in small wavelength wireless networks

ABSTRACT

Reduced signaling overhead is provided in an apparatus and method for communications within a mesh network. The communications involve using two different beacon signals. A peer beacon contains time synchronization and resource management information to maintain existing links among one or more neighboring peer stations, while a separate network discovery beacon contains mesh network profile information that identifies the mesh network to aid network discovery for wireless communication stations wanting to join the mesh network. Embodiments describe coordination between peer stations to determine which stations are to send the network discovery beacons, so that at any given period of time not all stations need to be transmitting the discovery beacons.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S.provisional patent application Ser. No. 62/550,028 filed on Aug. 25,2017, incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF COMPUTER PROGRAM APPENDIX

Not Applicable

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION

A portion of the material in this patent document may be subject tocopyright protection under the copyright laws of the United States andof other countries. The owner of the copyright rights has no objectionto the facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the United States Patent andTrademark Office publicly available file or records, but otherwisereserves all copyright rights whatsoever. The copyright owner does nothereby waive any of its rights to have this patent document maintainedin secrecy, including without limitation its rights pursuant to 37C.F.R. § 1.14.

BACKGROUND 1. Technical Field

The technology of this disclosure pertains generally to directionalwireless communications between stations, and more particularly to moreefficient use of beacon signaling within multiple-hop relayeddirectional wireless communication networks.

2. Background Discussion

Millimeter wavelength (mm-wave or mmW) wireless networks, including meshnetworks and mixtures of mesh and non-mesh networks, are becomingincreasingly important. Due to the need of higher capacity, networkoperators have begun to embrace concepts to achieve densification. Useof current sub-6 GHz wireless technology is not sufficient to cope withhigh data demands. One alternative is to utilize additional spectrum inthe 30-300 GHz band, millimeter wave band (mmW).

Enabling mmW wireless systems in general requires properly dealing withthe channel impairments and propagation characteristics of the highfrequency bands. High free-space path loss, high penetration, reflectionand diffraction losses reduce the available diversity and limitnon-line-of-sight (NLOS) communications. The small wavelength of mmWenables the use of high-gain electronically steerable directionalantennas of practical dimensions. This can provide enough array gain toovercome path loss and ensure high Signal-to-Noise Ratio (SNR) at thereceiver. Directional mesh networks in dense deployment environmentsusing mmW bands are an efficient way to achieve reliable communicationsbetween nodes and overcome line-of-sight channel restrictions.

A new station node starting up will be looking for neighboring nodes todiscover and a network to join. The process of initial access of a nodeto a network comprises scanning for neighboring nodes and discoveringall active nodes in the local vicinity. This can be performed eitherthrough the new node searching for a specific network/list of networksto join, or by the new node sending a broadcast request to join anyalready established network that will accept the new node.

A node connecting to a mesh network needs to discover neighboring nodesto decide on the best way to reach a gateway/portal mesh nodes and thecapabilities of each of these neighboring nodes. The new node examinesevery channel for possible neighboring nodes for a specific period oftime. If no active node is detected after that specific time, the newnode moves to test the next channel. When a node is detected, the newnode collects sufficient information to configure its PHY layer foroperation in the regulatory domain (IEEE, FCC, ETSI, MKK, etc.). Thistask is further challenging in mmWave communications due to directionaltransmissions. The challenges in this process can be summarized as: (a)knowledge of surrounding nodes IDs; (b) knowledge of best transmissionpattern for beamforming; (c) channel access issues due to collisions anddeafness; and (d) channel impairments due to blockage and reflections.Designing a neighborhood discovery method to overcome some or all of theabove is of utmost importance to enable pervasiveness of mmWave D2D andmesh technologies.

Most existing technologies for mesh networking address mesh discoverysolutions for networks operating in broadcast mode and is not targetedto networks with directional wireless communications. In addition, thosetechnologies which utilize directional wireless network communicationsoften have very high overhead demands in regards to the generation ofbeacon signals.

Accordingly, a need exists for enhanced mechanisms for beaconing withina mmWave network. The present disclosure fulfills that need and providesadditional benefits over previous technologies.

BRIEF SUMMARY

It is important to be able to setup and maintain mmWave communicationsin a mesh topology network without causing significant signalingoverhead or network discovery delay. In the disclosed technology twodifferent types of beacon signals are utilized: (1) a communicationbeacon (peer beacon) and (2) a discovery beacon. The use of these twobeacons allows separation of discovery function and network maintenancefunction, so a node station (STA) embeds less information in each ofthese strategically targeted beacons. Using the present apparatus andmethod with these separated beacons reduces signaling overhead.

The disclosed technology coordinates discovery beacon transmissionsamong STAs in a network, toward reducing unnecessary beacontransmissions for the purpose of network discovery. The disclosedapparatus and method defines a set of rules how the coordination shouldbe performed in an efficient manner. For example, the disclosedtechnology reduces the number of sectors for communication (peer) beacontransmission, to reduce the number of beacon frames to be transmitted.The disclosed technology also defines a set of rules which allow bothpassive scanning and active scanning with reduced beaconing overhead.Based on these rules, new stations (those seeking to join the meshnetwork) can discover an existing network with limited network delay.

A number of terms are utilized in the disclosure whose meanings aregenerally described below.

A-BFT: Association-Beamforming Training period; a period announced inthe beacons that is used for association and BF training of new stations(STAs) joining the network.

AP: Access Point; an entity that contains one station (STA) and providesaccess to the distribution services, through the wireless medium (WM)for associated STAs.

Beamforming (BF): a directional transmission that does not use anomnidirectional antenna pattern or quasi-Omni antenna pattern.Beamforming is used at a transmitter to improve received signal power orsignal-to-noise ratio (SNR) at an intended receiver.

BSS: Basic Service Set; a set of stations (STAs) that have successfullysynchronized with an AP in the network.

BI: the Beacon Interval is a cyclic super frame period that representsthe time between beacon transmission times.

BRP: BF Refinement protocol; a BF protocol that enables receivertraining and iteratively trains the transmitter and receiver sides toachieve the best possible directional communications.

BTI: Beacon Transmission Interval, is the interval between successivebeacon transmissions.

CBAP: Contention-Based Access Period; the time period within the datatransfer interval (DTI) of a directional multi-gigabit (DMG) BSS wherecontention-based enhanced distributed channel access (EDCA) is used.

DTI: Data Transfer Interval; the period whereby full BF training ispermitted followed by actual data transfer. It can include one or moreservice periods (SPs) and contention-based access periods (CBAPs).

ISS: Internal Sublayer Service.

MAC address: a Medium Access Control (MAC) address.

MBSS: Mesh Basic Service Set, a basic service set (BSS) that forms aself-contained network of Mesh Stations (MSTAs), and which may be usedas a distribution system (DS).

MCS: Modulation and Coding Scheme; defines an index that can betranslated into the PHY layer data rate.

MSTA: Mesh Station (MSTA): a station (STA) that implements the Meshfacility. An MSTA that operates in the Mesh BSS may provide thedistribution services for other MSTAs.

Omni directional: a non-directional antenna mode of transmission.

Quasi-Omni directional: a directional multi-gigabit (DMG) antennaoperating mode with the widest beamwidth attainable.

Receive sector sweep (RXSS): Reception of Sector Sweep (SSW) frames viadifferent sectors, in which a sweep is performed between consecutivereceptions.

RSSI: Receive Signal Strength Indicator (in dBm).

SLS: Sector-level Sweep phase: a BF training phase that can include asmany as four components: an Initiator Sector Sweep (ISS) to train theinitiator, a Responder Sector Sweep (RSS) to train the responder link asusing SSW Feedback and an SSW ACK.

SNR: received Signal-to-Noise Ratio in dB.

SP: Service Period; The SP that is scheduled by the access point (AP).

Scheduled SPs start at fixed intervals of time.

Spectral efficiency: the information rate that can be transmitted over agiven bandwidth in a specific communication system, usually expressed inbits/second or in Hertz.

SSID: service Set Identifier; the name assigned to a WLAN network.

STA: Station; a logical entity that is a singly addressable instance ofa medium access control (MAC) and physical layer (PHY) interface to thewireless medium (WM).

Sweep: a sequence of transmissions, separated by a short beamforminginterframe space (SBIFS) interval, in which the antenna configuration atthe transmitter or receiver is changed between transmissions.

SSW: Sector Sweep, is an operation in which transmissions are performedin different sectors (directions) and information collected on receivedsignals, strengths and so forth.

Transmit Sector Sweep (TXSS): transmission of multiple Sector Sweep(SSW) or Directional Multi-gigabit (DMG) Beacon frames via differentsectors, in which a sweep is performed between consecutivetransmissions.

Further aspects of the technology described herein will be brought outin the following portions of the specification, wherein the detaileddescription is for the purpose of fully disclosing preferred embodimentsof the technology without placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The technology described herein will be more fully understood byreference to the following drawings which are for illustrative purposesonly:

FIG. 1 is a timing diagram of active scanning performed in an IEEE802.11 wireless local area network (WLAN).

FIG. 2 is a node diagram for a mesh network showing a combination ofmesh and non-mesh stations.

FIG. 3 is a data field diagram depicting a mesh identification elementfor an IEEE 802.11 WLAN.

FIG. 4 is a data field diagram depicting a mesh configuration elementfor an IEEE 802.11 WLAN.

FIG. 5 is a schematic of antenna sector sweeping (SSW) in the IEEE802.11ad protocol.

FIG. 6 is a signaling diagram showing signaling of sector-level sweeping(SLS) in the IEEE 802.11ad protocol.

FIG. 7 is a data field diagram depicting a sector sweep (SSW) frameelement for IEEE 802.11ad.

FIG. 8 is a data field diagram depicting the SSW field within the SSWframe element for IEEE 802.11ad.

FIG. 9A and FIG. 9B are data field diagrams depicting SSW feedbackfields shown when transmitted as part of an ISS in FIG. 9A, and when nottransmitted as part of an ISS in FIG. 9B, as utilized for IEEE 802.11ad.

FIG. 10 is a wireless node topology of example wireless mmWave nodes ina wireless network as utilized according to an embodiment of the presentdisclosure.

FIG. 11 is a block diagram of station hardware as utilized according toan embodiment of the present disclosure.

FIG. 12 is a beam pattern diagram for the station hardware of FIG. 11 asutilized according to an embodiment of the present disclosure.

FIG. 13A through FIG. 13C is wireless node topology and associateddiscovery beacon sweeping according to an embodiment of the presentdisclosure.

FIG. 14 is a communication period diagram showing transmission andreception from a mesh node according to an embodiment of the presentdisclosure.

FIG. 15A through FIG. 15D is wireless node topology upon which a beaconmaster method is described according to an embodiment of the presentdisclosure.

FIG. 16 is an antenna pattern map of a coverage area showing the resultsof coordination between nodes according to an embodiment of the presentdisclosure.

FIG. 17 is a sector sweep diagram used for mesh network discovery framesaccording to an embodiment of the present disclosure.

FIG. 18A and FIG. 18B is a wireless node topology upon which bracketingof best sector communications directions are performed according to anembodiment of the present disclosure.

FIG. 19 is a flow diagram of transmitting peer beacons according to anembodiment of the present disclosure.

FIG. 20 is a flow diagram of training database creation and updatesaccording to an embodiment of the present disclosure.

FIG. 21 is a communication period diagram showing a beacon mastertransmitting discovery beacons in all directions according to anembodiment of the present disclosure.

FIG. 22 is a communication period diagram showing a peer beaconsuperframe format according to an embodiment of the present disclosure.

FIG. 23A through FIG. 23C are wireless node diagrams of master beaconforwarding and announcements performed according to an embodiment of thepresent disclosure.

FIG. 24A through FIG. 24C are wireless node diagrams of different nodestaking on the beacon master role according to an embodiment of thepresent disclosure.

FIG. 25A through FIG. 25E are wireless node diagrams of master beaconoutage handling according to an embodiment of the present disclosure.

FIG. 26A and FIG. 26B is a flow diagram of random master beaconselection according to an embodiment of the present disclosure.

FIG. 27A and FIG. 27B is a flow diagram of sequence based master beaconselection according to an embodiment of the present disclosure.

FIG. 28 is an antenna pattern map showing a coverage area of a coveragearea in response to cooperation between nodes according to an embodimentof the present disclosure.

FIG. 29A through FIG. 29C are node sector coverage diagrams utilizedaccording to an embodiment of the present disclosure.

FIG. 30 is a message passing diagram for a new node performing passivescanning to be admitted to the mesh network according to an embodimentof the present disclosure.

FIG. 31 is a message passing diagram for a new node performing activescanning for admission to the mesh network according to an embodiment ofthe present disclosure.

FIG. 32 is a node sector coverage diagram showing sector coveragebetween nodes utilized according to an embodiment of the presentdisclosure.

FIG. 33 is a node sector coverage diagram showing sector coveragebetween nodes with effects of movement of a new node through thecoverage area as responded to according to an embodiment of the presentdisclosure.

FIG. 34A and FIG. 34B is a flow diagram of a new node discovering andjoining a mesh network according to an embodiment of the presentdisclosure.

FIG. 35 is a flow diagram of beacon master handling of new nodeadmission according to an embodiment of the present disclosure.

FIG. 36A and FIG. 36B is a message passing diagram of admitting a newnode into the mesh network as orchestrated by a center controllerentity, which is outside the range of the new node, as performedaccording to an embodiment of the present disclosure.

FIG. 37 is a message passing diagram of admitting a new node into themesh network as orchestrated by a center controller entity, which iswithin the range of the new node, as performed according to anembodiment of the present disclosure.

FIG. 38A and FIG. 38B are communication period diagrams in performing anassisted discovery process according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

1. Existing Directional Wireless Network Technology

1.1. WLAN Systems

In WLAN systems, 802.11 defines two modes of scanning; passive andactive scanning. The following are the characteristics of passivescanning. (a) A new station (STA), attempting to join a network,examines each channel and waits for beacon frames for up toMaxChannelTime. (b) If no beacon is received, then the new STA moves toanother channel, thus saving battery power since the new STA does nottransmit any signal in scanning mode. The STA should wait enough time ateach channel so that it does not miss the beacons. If a beacon is lost,the STA should wait for another beacon transmission interval (BTI).

The following are the characteristics of active scanning. (a) A new STAwanting to join a local network sends probe request frames on eachchannel, according to the following. (a)(1) STA moves to a channel,waits for incoming frames or a probe delay timer to expire. (a)(2) If noframe is detected after the timer expires, the channel is considered tobe not in use. (a)(3) If a channel is not in use, the STA moves to a newchannel. (a)(4) If a channel is in use, the STA gains access to themedium using regular DCF and sends a probe request frame. (a)(5) The STAwaits for a desired period of time (e.g., Minimum Channel Time) toreceive a response to the probe request if channel was never busy. TheSTA waits for more time (e.g., Maximum Channel Time) if the channel wasbusy and a probe response was received.

(b) Probe Request can use a unique service set identifier (SSID), listof SSIDs or a broadcast SSID. (c) Active scanning is prohibited in somefrequency bands. (d) Active scanning can be a source of interference andcollision, especially if many new STAs arrive at the same time and areattempting to access the network. (e) Active scanning is a faster way(more rapid) for STAs to gain access to the network compared to the useof passive scanning, since STAs do not need to wait for beacons. (f) Ininfrastructure basic service set (BSS) and IBSS, at least one STA isawake to receive and respond to probes. (g) STAs in mesh basic serviceset (MBSS) might not be awake at any point of time to respond. (h) Whenradio measurement campaigns are active, nodes might not answer the proberequests. (i) Collision of probe responses can arise. STAs mightcoordinate the transmission of probe responses by allowing the STA thattransmitted the last beacon to transmit the first Probe Response. Othernodes can follow and use back-off times and regular distributedcoordination function (DCF) channel access to avoid collision.

FIG. 1 depicts the use of active scanning in an IEEE 802.11 WLAN,depicting a scanning station sending a probe and two responding stationswhich receive and respond to the probe. The figure also shows the minand max probe response timing. The values G1 is shown set to SIFS whichis the interframe spacing prior to transmission of an acknowledgment,while G3 is DIFS which is DCF interframe spacing, represented the timedelay for which a sender waits after completing a backoff period beforesending an RTS package.

1.2. IEEE 802.11s Mesh WLAN

The IEEE 802.11s (hereafter 802.11s) is a standard that adds wirelessmesh networking capabilities to the 802.11 standard. 802.11s defines newtypes of radio stations as well as new signaling to enable mesh networkdiscovery, establishing peer-to-peer connection, and routing of datathrough the mesh network.

FIG. 2 illustrates one example of a mesh network where a mix of non-meshSTA connect to Mesh-STA/AP (solid lines) and Mesh STAs connect to othermesh STA (dotted lines) including a mesh portal. Nodes in mesh networksuse the same scanning techniques defined in the 802.11 standard fordiscovering neighbors. The identification of the mesh network is givenby the Mesh ID element contained in the Beacon and the Probe Responseframes. In one mesh network, all mesh STAs use the same mesh profile.Mesh profiles are considered the same if all parameters in the meshprofiles match. The mesh profile is included in the Beacon and ProbeResponse frames, so that the mesh profile can be obtained by itsneighbor mesh STAs through the scan.

When a mesh STA discovers a neighbor mesh STA through the scanningprocess, the discovered mesh STA is considered a candidate peer meshSTA. It may become a member of the mesh network, of which the discoveredmesh STA is a member, and establish a mesh peering with the neighbormesh STA. The discovered neighbor mesh STA may be considered a candidatepeer mesh STA when the mesh STA uses the same mesh profile as thereceived Beacon or Probe Response frame indicates for the neighbor meshSTA.

The mesh STA attempts to maintain the discovered neighbor's informationin a Mesh Neighbors Table which includes: (a) neighbor MAC address; (b)operating channel number; and (c) the most recently observed link statusand quality information. If no neighbors are detected, the mesh STAadopts the Mesh ID for its highest priority profile and remain active.All the previous signaling to discover neighbor mesh STAs are performedin broadcast mode. It should be appreciated that 802.11s was nottargeted for networks with directional wireless communications.

FIG. 3 depicts a Mesh Identification element (Mesh ID element) which isused to advertise the identification of a Mesh Network. Mesh ID istransmitted in a Probe request, by a new STA willing to join a meshnetwork, and in beacon and signals, by existing mesh network STAs. AMesh ID field of length 0 indicates the wildcard Mesh ID, which is usedwithin a Probe Request frame. A wildcard Mesh ID is a specific ID thatprevents a non-mesh STA from joining a mesh network. It should berecognized that a mesh station is a STA that has more features than anon-mesh station, for example, it is like having the STA running as amodule in additional to some other modules to serve the meshfunctionality. If the STA does not have this mesh module it should notbe allowed to connect to a mesh network.

FIG. 4 depicts a Mesh configuration element is contained in Beaconframes and Probe Response frames transmitted by mesh STAs, and it isused to advertise mesh services. The main contents of the MeshConfiguration elements are: (a) a path selection protocol identifier;(b) a path selection metric identifier; (c) a congestion control modeidentifier; (d) a synchronization method identifier; and (e) anauthentication protocol identifier. The contents of the MeshConfiguration Element together with the Mesh ID form a mesh profile.

The standard 802.11a defines many procedures and mesh functionalitiesincluding: mesh discovery, mesh peering management, mesh security, meshbeaconing and synchronization, mesh coordination function, mesh powermanagement, mesh channel switching, three address, four address, andextended address frame formats, mesh path selection and forwarding,interworking with external networks, intra-mesh congestion control andemergency service support in mesh BSS.

1.3. Millimeter Wave in WLAN

WLANs in millimeter wave bands generally require the use of directionalantennas for transmission, reception or both, to account for the highpath loss and to provide sufficient SNR for communication. Usingdirectional antennas in transmission or reception makes the scanningprocess directional as well. IEEE 802.11ad and the new standard 802.11aydefine procedures for scanning and beamforming for directionaltransmission and reception over the millimeter wave band.

1.4. IEEE 802.11Ad Scanning and BF Training

An example of a mmWave WLAN state-of-the-art system is the 802.11adstandard.

1.4.1. Scanning

A new STA operates on passive or active scanning modes to scan for aspecific SSID, a list of SSIDs, or all discovered SSIDs. To passivelyscan, a STA scans for DMG beacon frames containing the SSID. To activelyscan: a DMG STA transmit Probe Request frames containing the desiredSSID or one or more SSID List elements. The DMG STA might also have totransmit DMG Beacon frames or perform beamforming training prior to thetransmission of Probe Request frames.

1.4.2. BF Training

BF training is a bidirectional sequence of BF training frametransmissions that uses sector sweep and provides the necessarysignaling to allow each STA to determine appropriate antenna systemsettings for both transmission and reception.

The 802.11ad BF training process can be performed in three phases. (1) Asector level sweep phase is performed whereby directional transmissionwith low gain (quasi-Omni) reception is performed for link acquisition.(2) A refinement stage is performed that adds receive gain and finaladjustment for combined transmit and receive. (3) Tracking is thenperformed during data transmission to adjust for channel changes.

1.4.3. 802.11ad SLS BF Training Phase

This focuses on the sector level sweep (SLS) mandatory phase of the802.11ad standard. During SLS, a pair of STAs exchange a series ofsector sweep (SSW) frames (or beacons in case of transmit sectortraining at the PCP/AP) over different antenna sectors to find the oneproviding highest signal quality. The station that transmits first iscalled the initiator, the second is the responder.

During a transmit sector sweep (TXSS), SSW frames are transmitted ondifferent sectors while the pairing node (the responder) receivesutilizing a quasi-Omni directional pattern. The responder determines theantenna array sector from the initiator which provided the best linkquality (e.g. SNR).

FIG. 5 depicts the concept of sector sweep (SSW) in 802.11ad. In thisfigure, an example is given in which STA 1 is an initiator of the SLSand STA 2 is the responder. STA 1 sweeps through all of the transmitantenna pattern fine sectors while STA 2 receives in a quasi-Omnipattern. STA 2 feeds back to STA 2 the best sector it received from STA1.

FIG. 6 illustrates the signaling of the sector-level sweep (SLS)protocol as implemented in 802.11ad specifications. Each frame in thetransmit sector sweep includes information on sector countdownindication (CDOWN), a Sector ID, and an Antenna ID. The best Sector IDand Antenna ID information are fed back with the Sector Sweep Feedbackand Sector Sweep ACK frames.

FIG. 7 depicts the fields for the sector sweep frame (an SSW frame) asutilized in the 802.11ad standard, with the fields outlined below. TheDuration field is set to the time until the end of the SSW frametransmission. The RA field contains the MAC address of the STA that isthe intended receiver of the sector sweep. The TA field contains the MACaddress of the transmitter STA of the sector sweep frame.

FIG. 8 illustrates data elements within the SSW field. The principleinformation conveyed in the SSW field is as follows. The Direction fieldis set to 0 to indicate that the frame is transmitted by the beamforminginitiator and set to 1 to indicate that the frame is transmitted by thebeamforming responder. The CDOWN field is a down-counter indicating thenumber of remaining DMG Beacon frame transmissions to the end of theTXSS. The sector ID field is set to indicate sector number through whichthe frame containing this SSW field is transmitted. The DMG Antenna IDfield indicates which DMG antenna the transmitter is currently using forthis transmission. The RXSS Length field is valid only when transmittedin a CBAP and is reserved otherwise. This RXSS Length field specifiesthe length of a receive sector sweep as required by the transmittingSTA, and is defined in units of a SSW frame. The SSW Feedback field isdefined below.

FIG. 9A and FIG. 9B depict SSW feedback fields. The format shown in FIG.9A is utilized when transmitted as part of an Internal Sublayer Service(ISS), while the format of FIG. 9B is used when not transmitted as partof an ISS. The Total Sectors in the ISS field indicate the total numberof sectors that the initiator uses in the ISS. The Number of RX DMGAntennas subfield indicates the number of receive DMG antennas theinitiator uses during a subsequent Receive Sector Sweep (RSS). TheSector Select field contains the value of the Sector ID subfield of theSSW field within the frame that was received with best quality in theimmediately preceding sector sweep. The DMG Antenna Select fieldindicates the value of the DMG Antenna ID subfield of the SSW fieldwithin the frame that was received with best quality in the immediatelypreceding sector sweep. The SNR Report field is set to the value of theSNR from the frame that was received with best quality during theimmediately preceding sector sweep, and which is indicated in the sectorselect field. The poll required field is set to 1 by a non-PCP/non-APSTA to indicate that it requires the PCP/AP to initiate communicationwith the non-PCP/non-AP. The Poll Required field is set to 0 to indicatethat the non-PCP/non-AP has no preference about whether the PCP/APinitiates the communication.

2. Problem Statement

Current millimeter wave (mmWave) communication systems, as described inthe previous section, typically need to rely heavily on directionalcommunication to gain sufficient link budget between transmitter andreceiver. In current systems, this process of determining the properbeam for use requires significant signaling overhead. For example, theAP transmits multiple beacon frames with transmit beam forming.

The beacon frames are used for network discovery purposes, i.e., passivescanning. For this reason, beacon frames are transmitted periodically,so that a new STA can recognize the existence of the network byperforming passive scanning in a certain time period.

To further complicate the situation, current technology is trendingtoward the use of finer beam forming, which allows higher antenna gainto secure better link budget. However, the overhead problem is furtherexacerbated when the STA employs finer beams, because the STA will betransmitting a larger number of beacon frames to cover a sufficienttransmission angle.

In view of the above, an important trade-off exists between beaconingoverhead and network discovery delay. If beacons are transmittedfrequently, then the beaconing overhead increases but allows a new STAto find the existing network quickly. If beacons are transmitted lessfrequently, the beaconing overhead can be decreased, however, it wouldbe difficult for a new STA to find the existing network in a rapidmanner.

When considering the task of forming a mesh network utilizing mmWave PHYtechnology, this overhead dilemma gets even worse. A STA connecting to amesh network needs to discover all neighboring STAs to decide on thebest way to reach gateway/portal mesh STAs and the capabilities of eachof these neighboring STAs. This means that all the STAs joining a meshnetwork should have the capability of beaconing which leads tosignificant signaling overhead.

Accordingly, the present disclosure is configured for addressing thesecurrent and future beacon overhead challenges.

3. Benefits of the Disclosed Efficient Beaconing

By utilizing the proposed technologies, mmWave communication nodes canform a mesh topology network without causing significant signalingoverhead or network discovery delay. The disclosed technology breaksbeaconing down into two different types of beacon signals: (1)communication beacon (peer beacon) and (2) discovery beacon. Creatingthese separate beacons allows separation of discovery function andnetwork maintenance function, so a STA can embed only the necessaryinformation to the function of each beacon. Using this separation ofbeacons in the manner described reduces signaling overhead.

The disclosed efficient beacon technology uses coordination of discoverybeacon transmissions among STAs in a network, to reduce unnecessarybeacon transmissions for the purpose of network discovery. Thistechnology defines a set of rules on how the communication transceiverscan perform this coordination in an efficient manner. The proposedtechnology reduces the number of sectors for communication (peer) beacontransmission, which allows a reduction of transmit beacon frames. Thistechnology defines a set of rules which allow both passive scanning andactive scanning with reduced beaconing overhead. Based on these rules,new STAs can discover existing network with limited network delay.

4. Efficient Beaconing Embodiments

4.1. Topology Under Consideration

FIG. 10 illustrates an example embodiment 10 of a network of mmWwireless nodes, in which mesh STA (MSTA) nodes 12, 14, 16 and 18 areconnected in a mesh topology with each other. A new STA 20 is scanning24, depicting directions 22 a-22 n, the communication medium forpotential neighboring MSTA and pair nodes.

It will be noted that directional transmission or reception is notrequired all the time at both sides. For example, one side might beperforming directional transmission or reception and the other side isnot. This might be due to limited capabilities of devices or theapplication requirement where there is no need for directionaltransmission from both side (limiting interference/small distance).

A new node can be configured with quasi-Omni directional or directionalantennas for transmission and reception. MSTAs can similarly be set upfor using Omni directional or quasi-Omni directional or directionalantennas for transmission and reception. At least one node MSTA, or thenew STA, should be configured with a directional antenna to providesufficient gain to account for the path loss and provide enough SNR forthe link.

A new STA scans for neighbors either using passive or active scanning.The new STA is configured to keep scanning until it finds allneighboring nodes. After a list of available MSTA neighbors areconstructed, a decision about which neighbor to connect with is made.This decision takes into account application demands, traffic loading inthe network and wireless channel status.

4.2. STA Hardware Configuration

FIG. 11 depicts an example embodiment 30 of node hardware configuration.In this example a computer processor (CPU) 36 and memory (RAM) 38 arecoupled to a bus 34, which is coupled to an I/O path 32 giving the nodeexternal I/O, such as to sensors, actuators and so forth. Instructionsfrom memory are executed on processor to execute a program whichimplements the communication protocols. This host machine is shownconfigured with a modem 40 coupled to radio-frequency (RF) circuitry 42a, 42 b, 42 c to a plurality of antennas 44 a-44 n, 46 a, 46 n, 48 a-48n to transmit and receive frames with neighboring nodes.

Although three RF circuits are shown in this example, embodiments of thepresent disclosure can be configured with modem 40 coupled to anyarbitrary number of RF circuits. In general, using a larger number of RFcircuits will result in broader coverage of the antenna beam direction.It should be appreciated that the number of RF circuits and number ofantennas being utilized is determined by hardware constraints of aspecific device. Some of the RF circuitry and antennas may be disabledwhen the STA determines it is unnecessary to communicate with neighborSTAs. In at least one embodiment, the RF circuitry includes frequencyconverter, array antenna controller, and so forth, and is connected tomultiple antennas which are controlled to perform beamforming fortransmission and reception. In this way the STA can transmit signalsusing multiple sets of beam patterns, each beam pattern direction beingconsidered as an antenna sector.

Antenna sector is determined by a selection of RF circuitry andbeamforming commanded by the array antenna controller. Although it ispossible that STA hardware components have different functionalpartitions from the one described above, such configurations can bedeemed to be a variant of the explained configuration. Some of the RFcircuitry and antennas may be disabled when the node determines it isunnecessary to communicate with neighbor nodes.

In at least one embodiment, the RF circuitry includes frequencyconverter, array antenna controller, and so forth, and is connected tomultiple antennas which are controlled to perform beamforming fortransmission and reception. In this way the node can transmit signalsusing multiple sets of beam patterns, each beam pattern direction beingconsidered as an antenna sector.

FIG. 12 illustrates an example embodiment 50 of antenna directions whichcan be utilized by a node to generate a plurality (e.g., 36) of antennasector patterns. In this example, the node implements three RF circuits52 a, 52 b, 52 c and connected antennas, and each RF circuitry andconnected antenna generates 12 beamforming patterns 56 a, 56 b, 56 c, onthrough to 56 n, as well as beamforming patterns 58 and 60; whereby itis said the node has 36 antenna sectors. However, for the sake ofclarity and ease of explanation, the following sections describe nodeshaving a smaller number of antenna sectors. It should be appreciatedthat any arbitrary beam pattern can be mapped to an antenna sector.Typically, the beam pattern is formed to generate a sharp beam, but itis possible that the beam pattern is generated to transmit or receivesignals from multiple angles.

4.3. Mesh Network Architecture

4.3.1. Beacon Functions

The functions of a beacon in a mmWave mesh network may comprise: (a)network discovery and association for new mesh nodes; (b)synchronization; (c) spectrum access and resource management. In theembodiments described herein, any signal that is used for the abovefunctionality is called a beacon, thus any signal used for thosepurposes should be interpreted as a beacon signal. In the next section,the 802.11 beacon is used to cover this functionality as an example,however other frames can be used to fulfill the same functionality.

4.3.2. Types of Beacons

Based on the different functionality of the beacons in the network, twotypes of beacons are proposed in the following embodiments, which arecommunication beacons (or peer beacons) and discovery beacons.

Communication or peer Beacons are utilized for communication betweenpeers with connections that have already (previously) been setup. Thisbeacon can be used for carrying out functions related to maintainingsynchronization, beam tracking and managing channel access and resourcesbetween mesh nodes in the network. Each mesh node sweeps beacons insectors corresponding to directions of neighbor nodes only and thustransmits beacons to its neighbors only.

Discovery beacons are utilized for network announcement and nodediscovery. The discovery beacons are used to aid the new nodes to findand join the mesh network. An existing mesh node sweeps the discoverybeacons in all directions it is intended to spatially cover. Thediscovery beacons can generally be transmitted less frequently than thepeer beacons to avoid uncoordinated beacon transmissions from differentnodes belonging to different mesh networks and limit interference.

FIG. 13A through FIG. 13C illustrate aspects of a simple networkconsidered by way of example and not limitation. In FIG. 13A exampleembodiment 70 is seen with three nodes 72, 74, and 76. In FIG. 13Bbeacons are shown transmitting from STA node 72, showing peer beaconsbeing swept 76 a, 76 b in directions corresponding to best sectorstowards nodes 74 and 76. In FIG. 13C STA node 72 sweeps 80 discoverybeacons to cover a specific spatial area from 78 a, 78 b, 78 c, 78 d,and 78 e.

FIG. 14 illustrates an example embodiment 90 of different transmissionand reception periods 98 of a mesh node across a time span 100. In thisexample the node operates in at least three periods according to thepresent disclosure. (1) A beacon interval 96 is the regular beacontransmission interval defined in 802.11. Communication or peer beaconsare transmitted every beacon interval to the node neighboring peers. (2)Discovery period 94 is the period of time (number of beacon intervals)that the node is transmitting discovery beacons in addition to the peerbeacons. Outside the discovery period, only peer beacons aretransmitted. Beacon Master Interval 92 is the period over which a noderepeats its discovery period and retransmits discovery beacons. If thediscovery period equals to the beacon master interval, the node istransmitting beacons all the time and acting as a regular 802.11 node.In the above and other embodiments described herein, it should beappreciated that discovery beacons do not have to take the form ofregular beacons. Discovery beacons can be any frames swept across someor all beam directions to announce the mesh network and discover newnodes. The periodicity or the isolated action of sending these frames inthat case can be defined independently of peer beacon periodicity.

4.3.3. Beacon Master and Beacon Master Functionality

A beacon master (BM) is a node selected at some time period to transmitthe discovery beacons. At any point in time, the beacon master is thenode that transmits the discovery beacon. Many nodes can be selected andscheduled to transmit discovery beacons at the same time, but it ispresented here the case where one beacon master is allowed at a timethrough the network to eliminate interference.

The functions of the beacon master may compromise the following: (a)sweeping of discovery beacons; (b) receiving and processing new BMrequests; (c) scheduling a new BM schedule based on received BMrequests; (d) updating a steady-state BM sequence; (e) defining thescanning receive directions for a new node joining the mesh network; (f)updating discovery beacon scanning directions for the peer nodes of anew node joining the mesh network.

4.3.4. System Architecture

4.3.4.1. Beacon Master Sequence

Every active node in the mesh network becomes a beacon master (BM)according to a selected sequence. This sequence remains valid until anew node becomes discoverable by an existing mesh node. The BM sequenceis modified to enable efficient discovery of the new node. If the newnode joins the network, the steady-state BM sequence will include a turnfor the new node to act as a BM.

FIG. 15A through FIG. 15D illustrates the beacon master concept. In FIG.15A mesh nodes A 112, B 114, C 116, D 118 are shown with a new node E120. In FIG. 15B node C is seen receiving a message from node Bcommunicating that it received (depicted by the arrow on top) a requestfrom node E to join the network. The next beacon masters (BMs) may beselected to be node B and node A, temporarily, as depicted by theshading seen in FIG. 15C. Then if node E joins the network, thesteady-state sequence of BM will include it.

4.3.4.2. Mesh Node Directional Passive Scanning Map for New Nodes

The following considers the situation in which mesh nodes are in an idlereception state, for example they are neither transmitting, norscheduled for receiving data from peer nodes. This embodiment proposes acoordinated passive scanning mode for a mesh node in which the nodeslisten directionally to probe requests from new nodes willing to jointhe network.

FIG. 16 depicts directions 130 to which the nodes listen, as seen by thedotted cones. In particular, node 132 a is seen listening in region 134a, node 132 b is seen listening in region 134 b, node 132 c is seenlistening in region 134 c, node 132 d is seen listening in region 134 d,node 132 e is seen listening in region 134 e, for as many as there arenodes in this local mesh. It is seen that these listening regions arearranged to provide sufficient reception coverage over area 136, so thatrequests are properly received from any new nodes within that region.

These directions may be coordinated by a central entity or locally andeach node may listen in on all or a subset of their receiver antennapattern sectors. The directions can be updated dynamically based oncurrent network scheduling or in a semi-static assignment based onaverage link usage. In the figure one can recognize the collaboration ofa few mesh nodes to cover signal reception for a given reception area.

4.3.4.3. New Node Active Scanning Mode

In at least one embodiment, a node willing to join a mesh network canperform active scanning of surrounding mesh nodes. The active scanningcan be performed via sweeping a probe request across different sectorssupported by the antenna pattern of this node.

FIG. 17 illustrates an embodiment 150 of a node 152 transmitting indirections 154 a through 154 n, during sweeping 156 of a mesh networkdiscovery frame in a quasi-Omni directional transmission.

4.4. Efficient BF Training through Peer and Discovery Beacons

4.4.1. Peer Beacon Updates

In directional communications, e.g. 60 GHz WLAN, beacon transmissionsmay be utilized in at least one embodiment of the present disclosure aspart of the BF training required to establish robust communicationsbetween peers. The discovery beacons described herein can initiate theBF training, such as for example using SLS phase.

A mesh node records the best sector information from the BF trainingthat happens during and shortly after transmitting the discoverybeacons. For peer beacons, the mesh node transmits beacons only insectors corresponding to best sectors towards peer mesh nodes.

FIG. 18A and FIG. 18B illustrate an example embodiment of providingadditional robustness, by performing transmissions on one or moresectors around (bracketing) the determined best sector. In FIG. 18A NodeA 172 is seen in relation to node B 174 with the best sector (path)being direction 176. In FIG. 18B Node A in communicating with node B hasbest sector 178 b, but also selects one or more additional sectors 178a, 178 c, on each side of this best sector to improve communicationsrobustness, especially in view of the fact that node B may be moving inrelation to node A.

FIG. 19 illustrates an example embodiment 190 of transmission of peerbeacons by a mesh node. The routine starts 192 and a check is performed194 if the beacon interval (BI) timer has expired. If it has not expiredthen the timer is decremented 196 before another check is performed. Itwill be noted that the use of a timing “loop” is shown for the sake ofillustration, however, providing the delays (synchronization) may beperformed by any desired operating system primitives, such assynchronization and timing mechanisms utilized within a threaded ormulti-tasking environment.

After the BI timer expires, then block 198 initializes a node count n,and then retrieves 200 best sector information S(n) towards node n, froma record 208 of best sectors. A sweep of communication beacons isperformed 202 to node n on sectors S(n)±q. A check is then made 204 ifany nodes still need to be checked (n<N). If there are nodes remaining,then the node value is updated 206 (e.g., n=n+1 in this example) to thenext node and processing returns back to step 200 in retrieving bestsector information. Once all nodes are checked then data exchange isperformed 210 with peer mesh node and the process ends 212.

FIG. 20 illustrates an embodiment 230 of training database creation andupdates. After a few beacon intervals (BIs), the BF training may need tobe updated. The discovery beacons provide either the refresh cycle ofthe BF training or a BF training with a new peer node.

The process commences 232 with discovery beacons being received 234 fromSTA n, followed by retrieval 236 of an entry of STA n in a record ofbest sectors from record of best sectors 238. A check 240 is made todetermine if STA n has an entry in the record of best sectors. If thereis no such entry, then an entry is made 242 into the record of bestsectors 238. Otherwise, if there is an existing entry, then the existingand current data are compared 244 and BF training information is updated246 for STA n prior to the processing ending 248.

4.5. Steady State BM Handling Protocol

4.5.1. Master Beacon Switching

The network in steady state moves (rotates) the beacon masters among thenetwork nodes, such as in a specific order according to at least oneembodiment of the invention.

FIG. 21 illustrates an example embodiment 250 of transmissions 252,showing a beacon master transmitting discovery beacons in all directions254, as well as peer beacon directions 260 a, and 260 b. In addition,transmission of Association-Beamforming Training period (A-BFT) 256 andData Transfer Interval (DTI) 258 are shown.

FIG. 22 illustrates an example embodiment 270 of a peer beaconsuperframe format, showing a set of transmissions 272. Nodes with peerconnectivity still continue to transmit peer beacons to each other. Inthis example a peer beacon is sent 274 a to peer 1, and a peer beacon issent 274 b to peer 2. An A-BFT transmission 274 c is sent for peer 1, aswell as an A-BFT transmission 274 d for peer 2. A DTI transmission 276is shown being sent after the A-BFT transmissions. It should berecognized that the peer beacons are easy coordinated since thedirection and the timing is known for each peer link

The system is configured in at least one embodiment, so that the orderof switching peer beacons provides that all nodes at some time act as abeacon master. It should be appreciated, however, that embodiments arealso contemplated which further control beacon master selection based onselect criterion, or that apply incentives (e.g., network messagepriority) to those participating as beacon masters.

Peer beacons as well as discovery beacons carry information about thecurrent beacon master node. Peer beacons as well as discovery beaconscarry information about future beacon master(s). This information can bethe ID of the next node to be a beacon master or a sequence ID thatdetermines the coming beacon master assignment. Peer beacons carryinformation related to scheduling of transmission and other elementsnecessary for synchronizations and data transmission for this peerconnectivity. Discovery beacons are simpler and are preferably (e.g., inone or more embodiments) only used for network announcement anddiscovery purposes. The A-BFT period for peer beacons will carry anumber of A-BFT slots equal to the number of active peer links as wasseen in FIG. 22. The A-BFT period of the discovery beacons carries alarger number of A-BFT slots with random access to these slots by peernodes and new nodes.

4.5.2. Peer Beacons for Managing Master Beacon Switching

FIG. 23A through FIG. 23C depict nodes interacting in a process offorwarding the master beacon announcement through the network by peerbeacons. Nodes are seen in the figures comprising MSTA A 292, MSTA B294, MSTA C 296, MSTA D 298, MSTA E 300. In each figure MSTA A 292 isseen as the beacon master which is transmitting discovery beacons 302 ina sweep 304 of all directions.

Once a mesh node takes over the master beacon rule, it startstransmitting discovery beacons and peer beacons with its ID as currentbeacon master and information about the next beacon master, sequence IDor next beacon master. Peer beacons will be received by the nodesconnected to the master beacon as an indication to the master beaconbeing active and starting its rule. Peers of the master beacon starttransmitting peer beacons to other mesh nodes in the network announcingthe new master beacon in the network. In FIG. 23A peer beacons 306 a,306 b announce to MSTA B 294 and MSTA B 296, respectively, that a newbeacon master is now active, and the timer setting. Each node receivingthe peer beacons with the new master beacon announcement forwards it toits peers. In FIG. 23A an old MB announcement was communicated 308 fromMSTA B 294 to MSTA E 300. After a specific number of hops the clustershould be informed of the new beacon master taking its rule. Until themesh node receives announcement of new master beacon activation throughone of its peers or the master beacon itself, it will keep transmittingthe old master beacon ID and timer equal to zero. This is to indicatethat the network is in transition state. FIG. 23B depicts the new MBannouncement being communicated 310 from MSTA B 294 to MSTA E 300, whilean old MB announcement 312 is seen communicated between MSTA E 300 andMSTA D 298. In FIG. 23C a new MB announcement is seen communicated 314from MSTA B 294 to MSTA E 300, with time BM time value having beendecremented twice.

4.5.3. New Master Beacon Selection Criterion

In this embodiment, the nodes of the network alternate which onefulfills the role of beacon master for each master beacon interval. Ateach master beacon interval one node takes the role of the beacon masterand transmits discovery beacons in all directions.

FIG. 24A through FIG. 24C illustrate an example embodiment 330 ofdifferent nodes taking the role of master beacon. Nodes are seen in thefigures comprising MSTA A 332, MSTA B 334, MSTA C 336, MSTA D 338, MSTAE 340. In FIG. 24A MSTA A 332 is the beacon master transmittingdiscovery beacons 342 in a sweep 344 of all directions. The other nodesB, C, D and E are seen transmitting peer beacons only between the peernodes. In FIG. 24B MSTA C 336 has become the beacon master and istransmitting discovery beacons 342 in a sweep 344 of all directions, andsimilarly in FIG. 24C MSTA B 334 assumes the beacon master role. Themaster beacon announces through the peer beacons and the discoverybeacon information about current and future beacon master as well astiming for transmission. The order over which the master beacon changescan be determined in any desired manner, such as random or according toa specific sequence, according to availability, or other criterion foreach given node. However, it should be considered that if nodes canalways “opt out” in any way, then sharing would be inequitable or worseno beacon master may be available. Whereby in at least one embodiment ofthe present disclosure, if mechanisms allow nodes to “opt out” offulfilling the beacon master role, then incentives are provided to nodeswhich are participating, such as given them a commensurate priority ofcommunications over the non-participating nodes.

FIG. 25A through FIG. 25E illustrate an example embodiment 350 of masterbeacon outage handling, which will be described in detail at the end ofthe next section.

4.5.3.1. Random Master Beacon Assignment

FIG. 26A and FIG. 26B illustrate an example embodiment 390 of a protocolfor deploying random master beacon selection. The routine starts withwaiting 392 in FIG. 26A to receive peer beacons, then modifying a masterbeacon selection variable, depicted here by decrementing 394 a masterbeacon countdown value, followed by the check if the value has reachedzero, indicating that checked new master beacon should be active. If thecurrent master beacon is still active, then execution returns to block392. Otherwise a check 398 is made to determine if the node is the newmaster beacon, based on checking what node the last beacon masterpreviously communicated as being the next (successor) beacon master. Ifit is not the new master beacon, then execution returns to block 392awaiting to receive peer beacons. Otherwise, if the node is to be thenew master beacon, then the node declares itself as a master beacon, andpicks the following master beacon, here exemplified by using a randompick 400 and setting a countdown timer. It will be appreciated that inat least one embodiment the next master beacon can be selected usingother mechanisms beside random selection.

Continuing in FIG. 26B, the master beacon performs its duties 402,including transmitting discovery beacons and peer activities includingtransmitting peer beacons and receiving other peer beacons, followed byupdating 404 the master beacon countdown, such as by decrementing it asper this example. A check is made 406 if the master beacon servingperiod is over (is master beacon counter=0), and if not, then executionreturns to block 402 with the current master beacon still performing itsduties. Otherwise, block 408 performs a check, if one peer beaconreports the new master beacon. If the one peer beacon reports the newmaster beacon, then execution returns to the beginning of the routine atblock 392 in FIG. 26A, otherwise decision block 410 is reached to checkif the new master beacon timer has expired. If the time has expired,then execution returns to block 400 in FIG. 26A, in which the nodedeclares itself the beacon master again and chooses a successor masterbeacon. Otherwise, if the timer has not expired, then execution returnsto decision block 408 to check again.

Therefore, the above flow diagram shows the process of the currentmaster beacon deciding which node is to be the next master beacon. Eachmesh node has a list of the other mesh nodes it can reach out to throughone or more hops. In this example the selection of the next masterbeacon is happening randomly from the list of the reachable nodes. Thecurrent master beacon forwards information regarding the current and thefuture master beacon through peer beacons and discovery beacons to allmesh nodes in the network. The current master beacons have a countdownfield to indicate when it will stop transmitting the discovery beaconsand when the new master beacon should start. Each node receiving a peerbeacon from the master beacon will decrement the countdown timer andforward the updated countdown value to its peers, the current beaconmaster ID and the next beacon master information to its peers throughits peer beacons. This will insure that the information propagatesthrough the whole network.

The countdown timer should be synchronized across the whole network.Every node should adapt the count down with respect to a fixed timewhere the counter should be decremented if it passes that time. This isconfigured for solving the problem when more than one BI are used acrossthe mesh network. If all the mesh nodes has the same BI, each nodeshould just decrement its countdown timer with each beacon transmission.When the counter reaches zero, the current master beacon stopstransmitting discovery beacons and assumes that the new master beaconwill take over.

4.5.3.1.1. Managing New Master Beacon Outage

The new master beacon should start transmitting discovery beacons andsending peer beacons stating the rule of the master beacon in the sentbeacons. Other nodes in the network will keep transmitting peer beaconswith master beacon ID of the one that concluded its task, with countdowntimer equals to zero until a new master beacon with new timerannouncement is received through the new master beacon or one peer node.

The master beacon that concluded its task will wait on receiving a signof the new beacon master taking over. This should be through receiving apeer beacon from one of its peer nodes stating the current master beaconas the one selected previously by the master beacon that concluded itstask.

In FIG. 25A through FIG. 25E the process 350 is outlined for the casewhen the master beacon, having concluded its task, did not receive anyindication of the new master beacon starting its task. Thus, theoriginal master beacon will again claim the master beacon role foranother master beacon cycle, and pick a new node to be the next masterbeacon.

In the figures nodes MSTA A 352, MSTA B 354, MSTA C 356, MSTA D 358 andMSTA E 360, are shown connecting with one another, In FIG. 25A MSTA A352 is the beacon master transmitting discovery beacons in all relevantdirections 362 in a sweep 364. Peer beacons 366 provide information onthe current beacon master (BM) which is MSTA A, next beacon master Awhich is exemplified as being MSTA C 356, and BM counter=x. In FIG. 25B,the peer beacons 368 indicate that BM counter has reached 0, and MSTA A352 is waiting 370 for MSTA C 356 to start acting as a beacon master.However, in this instance the communication links to MSTA C are broken,or MSTA C is not active or willing to fulfill the BM role. In FIG. 25C,the nodes MSTA B, MSTA C, MSTA D, and MSTA E, still are sending peerbeacons 368 indicating that the BM counter is 0 for MSTA C to fulfillthe BM role. Then upon timing out waiting for MSTA C to take the BMrole, the current BM then steps in 372 to continue fulfilling the BMrole and it sends peer beacons indicating the next BM to be MSTA E andsend a counter=x. In FIG. 25D, distant peer beacons 376 still indicatethat BM counter=0 awaiting MSTA C as BM, but MSTA A has taken the BMrole 374 and is sending a peer beacon indicating next BM as MSTA E, anddecrementing the BM counter. In FIG. 25E the peer beacons havepropagated throughout the network, and currently the peer beacons 378from MSTA A 352 indicate next BM as MSTA E and BM counter updated tox−2.

4.5.3.1.2. Beacon Master Selection Update Element

Upon adding a new node to the network, the selection list in each meshnode is updated to allow for this new node to be selected at some pointto serve as a beacon master. The master beacon can add the node to thelist by a message flooding the network stating an update to the meshnodes list. The node software (protocol) can also perform this byforcing the latest master beacon helping the new node to pick the newnode to serve as the master beacon right after it is admitted into thenetwork. Nodes will notice the new node serving as a beacon master andshould update their mesh node list.

When a node leaves the network, the selection list in each mesh node isupdated to remove this new node from the list and thus not to beselected at some point to serve as a beacon master. This removal of anode can be performed using message flooding of the network stating anupdate to the mesh nodes list or distributed by monitoring the behaviorof nodes in the network. If a node is not capable of serving as a beaconmaster for a number of discovery service periods, it will be removedfrom the list.

4.5.3.2. Sequence Based Master Beacon Assignment

FIG. 27A and FIG. 27B illustrate an example embodiment 430 of a protocol(process) for deploying a sequence based master beacon selection. Asequence determines the order of the nodes switching the role of beaconmaster is built and updated each time a new mesh node is joining. Theroutine commences 432 with awaiting to receive peer beacons, after whichthe master beacon counter is updated 434 (decremented by way of theexample shown), and a counter threshold check 436 performed to determineif the counter has reached a terminal value, in this case zero. If theterminal count has not been reached, then execution returns to waitingat block 432. Otherwise, if the count has expired, then a check 438 ismade if the node is the new master beacon. If it is not the masterbeacon, then execution moves to block 448 in FIG. 27B. If it is themaster beacon, then the node is declared 440 as a master beacon and acounter set for its duration as the master, followed by performingmaster beacon duties 442, exemplified with transmitting discoverybeacons, along with its peer duties in transmitting peer beacons, andreceiving peer beacons. The master beacon counter is then updated 444,counted down in this example, and a check made 446 if the end of thecount has been reached, which in this example is when it equals zero. Ifthe end of the count has been reached then execution moves back to block432, otherwise execution returns to performing another round of masterbeacon duties 442. From block 448 in FIG. 27B, it is seen that a checkis made to determine if a peer beacon has been received with a new MBtag. If a new MB tag was received, then execution returns to waiting atblock 432 in FIG. 27A, otherwise a wait is performed 450 to receive peerbeacons with a new master beacon tag and a non-terminal (non-zero inthis example) counter. A check is then made 452 for time expiration onthe new master beacon timer. If the new master beacon timer has notexpired, then execution returns to block 448 in checking for a peerbeacon with a new MB tag, otherwise execution moves to check 454 if thenode is the next master beacon after the failed one. If the node is notthe new master beacon, then execution returns to block 448 in checkingfor a peer beacon with a new MB tag. Otherwise the mode is the newbeacon master and execution returns to block 440 in which the nodedeclares itself as the new master beacon, and starts processing as such.

It will be noted that each time a new node joins the network, thecurrent master beacon is responsible for updating the sequence andinforming the network mesh nodes about that update. Once each node isaware of the sequence and the current active beacon master, it will beable to know the next beacon master and when its turn will arise. A BMcount is forwarded by the mesh nodes to mark the beginning and the startof a beacon master discovery period.

The BM counter, in this example a countdown timer, in at least oneembodiment is synchronized across the whole network. Every node shouldadapt the count down with respect to a fixed time where the countershould be decremented if it passes that time. This should solve theproblem when more than one BI are used across the mesh network. If allthe mesh nodes have the same BI, each node should just decrement itscountdown timer with each beacon transmission.

Once the timer reaches its terminal condition, such as zero in theexample shown, mesh nodes know that the new beacon master is takingover. If the mesh node is the new beacon master it starts transmittingdiscovery beacons and sets the BM counter value. The current masterbeacon forwards information regarding the current and the future masterbeacon through peer beacons and discovery beacons to all mesh nodes inthe network. The beacon sent by the current master beacon has a counterfield to indicate when it will stop transmitting the discovery beaconsand when the new master beacon should start.

Each node receiving a peer beacon from the master beacon modified the BMcounter toward a terminal value, such as decrementing the countdowntimer, and forwards the updated BM counter value to its peers, alongwith the current beacon master ID and the sequence ID through its peerbeacons to insure that this necessary information propagates through thewhole network. The new master beacon starts transmitting discoverybeacons and sending peer beacons stating the rule of the master beaconin the sent beacons.

4.5.3.2.1. Managing New Master Beacon Outage

If after some waiting time the new Master Beacon did not start its role,the next master beacon in the sequence should take over and claim themaster beacon rule, set the counter and start informing the mesh nodes.

4.5.3.2.2. Beacon Management Hopping Sequence Update Element

The beacon master is responsible for updating the sequence of the beaconmaster nodes. The update should be a result of a new node joining thenetwork or a node leaving the network. The distributed information canbe in the form of a sequence ID that is associated with a sequence. Eachnode should be capable of knowing its location in that sequence.

4.5.4. Triggering Discovery Beacons Transmission

One way of implementing the discovery beacon is to trigger it wheneverthere is a new event in the network. This means that the transmission ofthe discovery beacons does not have to be periodic. This event can be anew node sending a probe request that was received by one mesh node, amesh node losing connection, or any other event that requires full sweepof the beacon or similar frame in all directions for discovery andbeamforming reasons. This event might trigger one or more mesh nodestransmitting discovery beacons.

4.6. Discovery Mesh Map

Mesh nodes listen during the no activity periods (no transmission orreception) and scan for new nodes trying to join the network. Nodes canlisten in quasi-Omni directional mode to be able to scan all directionat the same time, although the range is limited. To Increase the rangeof the mesh node scanning for new nodes, directional antenna operationsare then selected by the system in at least one embodiment. Typically,using the directional antennas involves a process of each node scanningall directions.

However, if the node topology comprises a dense network deployment, thennode coverages will likely overlap, and at least one embodiment of thepresent disclosure then performs coordination of areas where each nodeis to perform scanning for new nodes, thus covering a geographic areamore efficiently.

FIG. 28 illustrates an example embodiment 470, in which each node isgiven responsible for one or more specific direction(s) which it willcontinuously and solely monitor whenever the node is not transmitting orreceiving. This will help in focusing the time the node is available inone direction instead of distributing it in all directions. In thisexample, a discovery map is cooperatively created by the nodes (in whicheach node is allocated one or more specific directions to monitor andscan. The discovery map can be generated using measurement campaigncollection, topology information of the network or some antenna patternanalysis.

In the example shown in FIG. 28, example mesh node MSTA A 472 is shownassigned area 474 a and 474 b, mesh node MSTA B 476 is shown assignedarea 478 a and 478 b, mesh node MSTA C 480 is shown assigned area 482 aand 482 b, mesh node MSTA D 484 is shown assigned area 486, mesh nodeMSTA E 488 is shown assigned area 490, mesh node MSTA F 492 is shownassigned area 494, and mesh node MSTA G 496 is shown assigned area 498.Thus, each mesh node is responsible for a specific area (direction) toscan whenever it is engaged in any other transmission or reception withother nodes in its network.

In at least one embodiment of the present disclosure, the analyticalcell planning is based on estimating at each area what the potentialmesh nodes are that cover this area and select one to be dedicated tothis area. A simple distributed way of deciding on coverage area ofsectors is by allowing sectors that are in line of sight and can listento each other's transmissions to shut off one of them and consider theother one to be capable of reaching out to all its coverage area.

FIG. 29A through FIG. 29C illustrates an example embodiment 510 ofdetermining new node coverage areas. In each figure MSTA A 512 and MSTAB 514, are shown with directional antenna sectors 516 a (S1) through 516d (S4), and 518 a (S1) through 518 d (S4), respectively.

In FIG. 29A MSTA A 512 and MSTA B 514 are in line of sight, and it isassumed that since direction 516 a (S1) of MSTA A 512 can communicatewith direction sector 518 c (S3) of MSTA B 514, then any node in betweenthese nodes can be reached by one of the two direction sectors.Therefore, each of these sectors can claim this coverage as itsdiscovery area.

In FIG. 29B and FIG. 29C, expected coverage areas 520 and 522 are seenfor MSTA A and MSTA B, respectively. In this embodiment, the presentdisclosure determines areas based on collecting measurements. In thisexample, the mobile station and other stations connected to the meshnetworks are collecting information about their location and what nodescan be seen. These lists are processed collectively to formrelationships between them. The outcome is that estimates are generatedof potential coverage area for each sector. The more stations that arein the network, the more accurate the estimate of the coverage area ofthese node sectors. Also as nodes are moving and discovering new nodes,an update is sent with new sets of nodes/sectors that can be discovered.The mobile nodes are discovering and losing sight with other nodes andforming new lists of neighbors that can be seen simultaneously. Theselists are saved and periodically processed.

In at least one embodiment, a centralized procedure is adopted in whichnodes are sending a report of location and the discovered sectors listto a central entity. The central entity collects all lists from allnetwork nodes and forms the discovery map. The central entity sends ascanning map to each node and informs it about its discovery area afterprocessing the collected lists. The nodes can send a report of all listscollected over a period of time periodically or momentarily once thenode location or discovered sectors changes to update the networkinformation.

4.7. New Node Discovery

The system is configured so that a new node can use passive or activescanning to search for nodes and discover neighbors in the network. Anew node passively scanning for neighbors is looking for the beaconmaster beacons. The nodes in the network are not concurrently sendingbeacons at the same time and every node in the network gets anopportunity to serve as a beacon master. The new node should hear abeacon from a nearby node once it is serving as a beacon master.

4.7.1. Full Passive New Node Scanning

In at least one embodiment, a new node can use only passive scanning toconnect to the mesh network. This approach is suitable for nodes that donot have time requirements to connect to the network or discover allneighbors. This is performed according to at least two differentembodiments.

4.7.1.1. Waiting for Beacon Master Beacons

A new node waits for all neighboring nodes to serve as master beaconsand receives its beacons. After a period of time equal to the totalnumber of nodes multiplied by the discovery period (master beaconserving period) after the first master beacon is received, the new nodeshould have completed the scanning period. If the node is tuned topassive scanning only, in the sequence based beacon master switching,when the new node receives the same beacon again it knows that itconcluded the scanning period. According to this embodiment, the newnode is configured to then contact the current master beacon to beincluded in the master beacon interval. The current master beacon shouldupdate the beacon master sequence or the list of mesh nodes in each meshnode. The discovery period can be adjusted so that the connectivitydelay is tolerated for new node joining. A new node can utilizequasi-Omni or directional antennas for scanning.

4.7.1.2. Triggering New Node Admission

In this embodiment new node admission is triggered in response toreceiving a beacon from a beacon master. A new node is waiting for abeacon from the current master beacon. Once a beacon is received, thistriggers the new node admission protocol. The new node keeps listeningfor master beacons. If the node is tuned to passive scanning only, inthe sequence based beacon master switching, when the new node receivesthe same beacon again it knows that it concluded the scanning period. Inthis embodiment the new node is configured to contact the current masterbeacon to start the node admission sequence. The current master beaconshould update the beacon master sequence or the list of mesh nodes ineach mesh node. The neighboring nodes to the new node will sequentiallystart transmitting beacons and claim temporary beacon master role. Thediscovery period can be adjusted so that the connectivity delay istolerated for new node joining. The new node can utilize quasi-Omni ordirectional antennas for scanning.

4.7.2. Passive/Active New Node Scanning

The new node can start with passive scanning looking for beacons fromthe current beacon master. If it happens that a node receives a beaconfrom the current beacon master, it will notify the beacon master of itsexistence and the current beacon master triggers the new node admissionprotocol. If the new node did not receive any beacon it will send aprobe request from a quasi-Omni antenna or multiple probe requests inall directions. Once a mesh node receives the probe request it willrespond with a probe response and inform the current beacon master aboutthe existence of the new node. The current beacon master will triggerthe new node admission protocol. The new node might decide to send aprobe request directly without looking for beacon masters to reduce theconnectivity time.

4.7.3. New Node Admission Protocol

Once the beacon master is notified of the new nodes existence it willtrigger the new node admission protocol. The new node can notify thecurrent beacon master itself if it received a discovery beacon from thebeacon master and can communicate directly with the beacon master. Othermesh nodes can notify the current beacon master about the existence ofthe new node when they receive a probe request from the beacon master.The beacon master schedules a campaign to help the new node in joiningthe network. This is performed by interrupting the current scheduledbeacon master sequence or future assignment, and scheduling nodes aroundthe new node to serve as a beacon master for a time periodequal-to-or-less-than the discovery period.

Every node stores the list of nodes in its geographical discovery map.This list includes nodes that are potential neighbors for any new nodediscovered by this neighbor or node. The nodes in the geographicdiscovery map of the mesh node that discover the new node serve asbeacon masters and transmit discovery beacons in all direction insequential order. The new node, after discovering the first mesh node,is listening for more discovery nodes for a selected period of time. Forexample, the new node might discover one or more of the nodes that arescheduled to serve as beacon masters and in the geographical discoveryzone of the mesh node that first discovered the new node. After the newnode discovery timer expires, the new node concludes its neighbordiscovery and scanning process. The new node selects neighbors toconnect to, and establishes a connection to the mesh network. The beaconmaster selection process then returns to normal operations and continuesthe sequence of future selection before the new node admission protocol.The new node listens to peer beacons from which it determines thecurrent master beacon. The new node sends the master beacon a request toserve as future master beacon if it is required to transmit discoverybeacons. The master beacon processes the request and adds the new nodeto the current sequence, or updates the list of MB nodes in each meshnode. The master beacon determines the discovery beams to be used aswell as if they are required. The process of scheduling new masterbeacons to help the new node, adding the new node to the sequence or thelist of the future possible master beacons in the nodes, and determiningthe discovery direction for nodes, can be performed in at least oneembodiment utilizing a centralized entity outside the master beacon thatcan be reached by any node.

The new node can keep listening for a long enough period of time to makesure that all nearby nodes have the opportunity to serve as beaconmasters and hence all neighbors have been discovered or might ask themesh node to expedite the discovery process by triggering the new nodeadmission protocol. However, the process of waiting for one of thenearby nodes to serve as a beacon master can be time consuming if thenetwork has many nodes or if the master beacon serving interval is long.

FIG. 30 is an example embodiment 530 of new node admission in responseto passive scanning within the BM coverage area. The figure showscommunications between new node 432, neighbor 1 node 534, neighbor 2node 536, neighbor 3 node 538, beacon master 540 and mesh node 542. Thebeacon master (BM) triggers the sequence to change BMs for assisting thenew node in joining the network quickly. The BM sends the BM scheduleupdate to force other nodes around the new node to send discoverybeacons. The new node 532 listens for discovery beacons sent from beaconmaster 540, as it sends discovery beacons in all directions 544, 548 and546. In this example, the new node is in range of beacon master 540 asit receives discovery beacon 544, to which it sends response 550. Thecurrent beacon master 540 announces 552 a beacon 554, 556, 558, 560,561. In some instances the beacon master sends the schedule and someinformation 561 to help the new node finding the neighbors too. The newnode receives discovery beacons 568 from a new beacon master neighbor 3node 538 which sends these discovery beacons in all directions 562, 564,566. The new node responds 570 with a beacon response. Similarly,discovery beacons are sent in all directions 572, including directions574, 576 and 578 by subsequent beacon master neighbor 2 node 536. Thendiscovery beacons are sent in all directions 580, including directions582, 584 and 586 by subsequent beacon master neighbor 1 node 534, towhich the new node sends beacon response 588, followed by a registrationrequest 590 to join the network. The beacon master then updates thebeacon master schedule and sends it out 594, 596, 598, 600 and 602 toall nodes.

FIG. 31 illustrates an example embodiment 610 of new node admission inresponse to active scanning within the BM coverage area. The figureshows communications between new node 612, neighbor 1 node 614, neighbor2 node 616, neighbor 3 node 618, beacon master 620 and mesh node 622.One BM is active, but when a new node is detected the BM sequencechanges to add neighboring nodes to the new node to expedite thediscovery process.

It is seen above, that the node can chose to actively search, accordingto an embodiment of the present disclosure, for neighbors by sending aprobe request in all directions, or sending the probe request using aquasi-Omni antenna. The new node receiving a probe response from one ofthe mesh nodes in response to its probe request, triggers the new nodeadmission protocol to kick in. The new node admission protocolinterrupts the next master beacon picked by the current master beacon orthe current sequence and enforces the neighboring nodes to the new nodeto serve as master beacons in sequence to give the new node theopportunity to discover nearby neighbors quickly. The determination ofpossible neighboring mesh nodes can be performed by defining ageographical discovery map for each node or sector. The geographicaldiscovery map for each node or sector represents a list that defines thepotential neighboring nodes/sectors if the new node is discovered bythat node or sector. After the new node discovers all its neighbors andconnects to the mesh network, the current master beacon is responsiblefor adding the new node to the list of available nodes at each node, orthe master beacon sequence list depending on the master beacon selectionmethod used in the mesh.

4.7.4. Geographical Discovery Zone

A geographical cluster of nodes are created for each MSTA or MSTAsector. For each node sector, the area that this sector is coveringrepresents the foot print of this sector. A set of possible neighboringnodes, or node sectors, that can be discovered in the foot print of thissector comprises the geographical discovery node or sector set. This setcontains nodes or sectors that might be seen by any new node discoveredby, or in this sector. Not all the members of this set should bediscovered by the new node, but it represents all possible potentialneighbors. In at least one embodiment, this set is updated any time anew node is joining the network, to include new MSTAs joining. This setcan be constructed either using measurement campaign collection,topology information of the network, or some form of antenna patternanalysis.

FIG. 32 illustrates an example embodiment 710 of a node or sectorgeographical discovery set (sector coverage area). The figure depictsnode MSTA A 712 with sectors 718 a through 718 d, MSTA B 714 withsectors 720 a through 720 d, and MSTA C 716 with sectors 722 a through722 d, depicting their overlapping antenna direction sectors. It can beseen from the figure that any node discovered by MSTA A 712, Sector 3(S3) 718 c can have MSTA C 716 (S1) 722 a and (S2) 722 b, and/or MSTA B714 (S4) 720 d as neighbors as well. Any node discovered by MSTA B 714(S1) 720 a, will only have MSTA A 712 (S2) 718 b as a potentialneighbor. The formation of the geographical discovery zones can beperformed by the system through measurement reporting in the network orby utilizing an analytical cell planning process.

In at least one embodiment, analytical cell planning is based onestimating potential neighbors at each coverage area of a node's sectorand loading the list at the node sector. To generate this list throughmeasurement reporting, a centralized or distributed procedure can beused. Each node/sector keeps a list of the neighboring nodes/sectorsthat can be discovered by this node/sector. These lists are processedcollectively to form relationships between them, and generating anoutcome estimating potential neighbors for each sector, if that sectoris discovered. The more nodes that exist in the local network the moreaccurate will the resultant estimate of the discovery zones be. Inaddition, as nodes are moving and discovering new nodes, updates aresent with new sets of nodes/sectors that can be discovered. Mobile nodesare being discovered, while others are lost sight of, with other nodesforming new lists of neighbors that can be seen simultaneously. Theselists are saved and periodically processed.

In the centralized procedure, nodes are sending neighboring lists foreach sector to a central entity. The central entity collects all listsfrom all network nodes and forms the geographical discovery zone. Thecentral entity sends a geographical discovery zone set to each nodeafter processing the collected lists. In at least one embodiment, thenodes (periodically or momentarily) send a report of all lists collectedover a period of time once the neighboring list changes to update thenetwork information.

In the distributed procedure, nodes send each of these lists to allmembers of these lists. In at least one embodiment of this case themoment the list is updated it is sent to all members of the list beforethe node loses sight of any of the list members. Once a node receives alist from another node, it adds all the members of the list to thediscovery zone of the sector that was received from.

FIG. 33 illustrates an example embodiment 730 as a variation of the caseshown in FIG. 32, depicting the case of a node moving and forming newlists. These lists are used to update the geographical discovery zoneset for these neighbors as shown in the table. The figure depicts nodeMSTA A 712 with sectors 718 a through 718 d, MSTA B 714 with sectors 720a through 720 d, and MSTA C 716 with sectors 722 a through 722 d,depicting their overlapping antenna direction sectors. A mobile node isshown moving through the antenna sectors associated with the three fixednodes, with mobile nodes intermediate locations seen as 740 a through740 f, as new lists are created when the neighbor associations changefrom MSTA A 712 (S4) as sole neighbor at L₁ 740 a, to neighbors MSTA A712 (S4) and MSTA C 716 (S1) at L₂ 740 b, to MSTA C 716 (S1) as soleneighbor at L₃ 740 c, to MSTA A 712 (S3) and MSTA C 716 (S1) at L₄ 740d, to MSTA A 712 (S3), MSTA C 716 (S1), and MSTA B 714 (S4) at L₅ 740 e,and finally to MSTA A 712 (S3) and MSTA B 714 (S4) at L₆ 740 f.

Table 1 details the neighbor list and discovery zone updates for theexample of FIG. 33 for each of the moving node positions L₁ through L₆.

4.7.5. New Node Discover Protocol

FIG. 34A and FIG. 34B illustrate an example embodiment 750 of aprocedure for a new node to discover and join a mesh network. Theprocess starts 752 and the new node searches waiting 754 for discoverybeacons, such as for a specific period of time equals to X. This timercan take many values to define multiple modes of operation. In block 756a check is made for discovery beacons received from the master beacon.If a discover beacon was received then execution moves forward to block764, otherwise decision block 758 is reached which checks if the initialdiscovery MB timer (X) has expired. If the time period has not yetcompleted, then execution goes back to block 754, otherwise it moves onto block 760 to send a probe request, and then to check 762 if a proberesponse was received. If no probe request received it goes back toblock 760 to send another probe request. Otherwise, if a response wasreceived, then it moves to block 764 to receive discovery beacons andmove on to check 766 in FIG. 34B which checks if a second discovery MBtimer has expired. If no expiration, then execution moves back to block764 in FIG. 34A, Otherwise, with the second discovery MB timer expiring,at block 768 connection is established from the new node to itsneighbors, and then the new node registers 770 with the MB as a futureMB, and the process ends 772.

In this embodiment, the following are preferred mechanisms by which theBM timing counter X is handled. If X equals its maximum value this meansthat the node is in full passive mode and will only wait for discoverybeacon from network beacon masters. If X equals zero, the node will notwait for discovery beacons and will go directly into active scanning. IfX equals an intermediate value (between 0 and “infinity”), it will givethe node the opportunity to receive discovery beacons if it was in itsvicinity and if not it will switch to active scanning.

If a discovery beacon is found, the new node remains in passive scanningexpecting more discovery beacons from nearby mesh nodes. If no discoverybeacon is found, the new node switches to active scanning and transmit aprobe request from a quasi-Omni antenna or sequentially in alldirections. When the new node receives a Probe Response it switches toPassive mode and starts scanning for discovery beacons. The search fordiscovery beacons continues for some specific timer value and after thisthe new node concludes it scanning and establish connection with thenetwork. The new node sends a registration request to the beacon masteror the central controller to be included in the beacon master futureschedule.

4.7.6. Current BM Protocol for Handling New Node

FIG. 35 illustrates an example embodiment 790 a beacon master handling anew node admission procedure. The current BM is informed about a newnode either by a new node responding to one of the discovery beaconsbeing transmitted in all directions, or through an announcement frameforwarded to MB through the mesh network. The beacon master updates thefuture schedule of the beacon master nodes and informs network meshnodes. The beacon master propagate the new sequence or the list of nodesto be scheduled to the whole mesh network through peer beacons. After afew beacon intervals the new beacon master schedule should be known tothe whole mesh network. The current master beacon stops transmittingmaster beacon and the new assigned nodes are taking place.

The routine starts 792 and waits 794 for new node announcements. Uponreceiving a new node announcement, a check 796 is made if the new nodeis responding to the discovery beacon. If the new node is not respondingto the discovery beacon, then block 798 is reached with a check made ifa mesh node is announcing the new node. If the new node announcementdoes not arise from either the discovery beacon or a mesh nodeannouncement, then execution returns to block 794 to await a new nodeannouncement. Otherwise, if the new node announcement arises from eitherthe discovery beacon or a mesh node announcement then execution reachedblock 800 where an update is performed to future beacon mastersaccording to the geo discovery zone, and block 802 is reached whichstops transmitting discovery beacons prior to the process ending 804.

4.8. Centralized Discovery Beacon Management

In this example embodiment a centralized entity fulfills one or moreroles that are assigned to the beacon master. This centralized controlcan facilitate the process of reaching out to the controller of thenetwork to admit a new node or to update the scheduling and scandirectionality of the network. In this embodiment, nodes do not need tobe aware of the current beacon master but they should be capable ofcommunicating with the central controller. The central controller isresponsible for selecting the future beacon masters or updating thesequence, orchestrating new node beacon master scheduling, handling thecase where a node is turned off or had a failure issue, and handling thediscovery map of the network. In case of no active beacon master, and noperiodic discovery beacon transmission, the central controller isresponsible for triggering the transmission of discovery beacons afterdetecting some events, such as a new node joining or losing connection.This can include triggering one or more mesh node discovery beacontransmissions. Also this process can include coordinating thetransmission of these beacons among those mesh nodes.

FIG. 36A, FIG. 36B, and FIG. 37 illustrate example embodiments 810, 910of a network procedure to admit a new node as orchestrated by a centralcontroller entity. In FIG. 36A and FIG. 36B the new node is outside ofthe coverage range of the beacon master, while in FIG. 37 the new nodeis within the beacon master coverage range.

If the new node receives a beacon from the beacon master, It will informthe beacon master and the beacon master communicates with the centralcontroller to schedule the neighboring node to help the new node.

In FIG. 36A and FIG. 36B a number of network entities are depicted asnew node 812 seeking to join the network, neighbor 1 node 814, neighbor2 node 816, neighbor 3 node 818, beacon master 820, central entity 822and mesh node 824. Referring to FIG. 36A, discovery beacons aregenerated 826 in all directions from beacon master 820 toward 828 newnode 812, toward 830 central entity 822, and toward 832 neighbor 816. Itwill be noted that these discovery beacons do not reach the new node.

Since the new node is not receiving the discovery beacons, it generates834 probe requests in all directions, seen as being toward 836 neighbor2 node 816, toward 838 neighbor 1 node 814, and toward 840 neighbor 3node 818. In response to this, neighbor 1 node 814 sends a proberesponse 842 to the new neighbor, and it announces 844 the new node tocentral entity 822. Then an announcement beacon master schedule update846 is generated by the central entity 822 with announcements 848, 850,852, 854, and 856, going out to the nodes excepting the new node. Whenhelpful, the neighbor that discovered the new node sends the new node aframe to inform the node about the new schedule and provide someadditional information that aids in beamforming with other neighbors.

Neighbor 3 node 818 is scheduled as a new temporary beacon master andgenerates 858 discovery beacons in all directions 860, 862, 864.

In FIG. 36B the new node 812 generates a beacon response 866 to Neighbor3 node 818. Then neighbor 2 node 816 generates 868 discovery beacons inall directions 870, 872 and 874. Then neighbor 1 node 814 generates 876discovery beacons in all directions 878, 880 and 882. Potentialneighbors have to send beacons in all direction to beam form with thenew node. A response 884 is generated from the new node to the bestbeacon of each neighbor. The new node might only receive one or perhapsa few of the beacons sent in all directions. The new node response isfollowed by the new node sending a BM registration request 886 tocentral entity 822. Central entity 822 sends out 890, 892, 894, 896,898, 900 a beacon master schedule update 888 to all parties.

In FIG. 37 embodiment 910, a number of network entities are depicted asnew node 912 seeking to join the network, neighbor 1 node 914, neighbor2 node 916, neighbor 3 node 918, beacon master 920, central entity 922and mesh node 924. Beacon master 920 sends 926 discovery beacons in alldirections, 928, 930 and 932, with these beacons reaching the new nodein this case. The new node 912 responds with beacon response 934 to thebeacon master 920 which announces 936 the new node to the central entity922. The central entity then announces 938 the beacon master schedule toall nodes 940, 942, 944, 946, 948, except the new node 912. Whenhelpful, the neighbor that discovered the new node sends the new node aframe to tell that node about the new schedule and some information thataids beamforming with other neighbor. Neighbor 3 node 918 generates 950discovery beacons in all directions 952, 954, 956. New node 912 respondswith a beacon response 958 to neighbor 3 node 918. Neighbor 2 node 916generates 960 discovery beacons in all directions 962, 964, 966. It willbe noted that the new node does not respond to this, likely it is out ofrange. Neighbor 1 node 914 generates 968 discovery beacons in alldirections 970, 972, 974. New node 912 responds with a beacon response976 to neighbor 1 node 914. New node 912 sends a registration request978 to central entity 922. The central entity 922 then announces 980 thebeacon master schedule to all nodes (including the new node as it is nowscheduled as a beacon master) 982, 984, 986, 988, 990, 992.

Thus, in view of the above it is seen that if the new node finds aneighbor node by sending a probe request and received a probe response,that neighbor node will communicate with the central controller toschedule the neighboring node to help the new node. The centralcontroller updates the beacon master schedule to assist the new node andmanage going back to the previous schedule when the new node admissionprotocol is completed. Upon the new node connecting to the network, itcan send a registration request to the central controller to be includedin a future beacon master schedule and to adjust its discovery scanningmap. The central controls respond by updating the network beacon masterschedule and the discovery scanning map through the whole network.

4.9. Efficient Mesh Cooperation for New Node Neighbor Discovery

Once the mesh node is informed of the existence of the new node eitherthrough passive or active scanning, the mesh coordinates the discoveryprocess among the mesh nodes. Nodes are scheduled to transmit theirnetwork announcement frames in all direction during the data transferinterval (DTI) period that serves the same function as the discoverybeacon but can be transmitted in the DTI period. Each mesh node repeatsthe transmission of the beacons for many cycles depending of thecapabilities of the new node. After the mesh node is completed, a newmesh node starts transmitting its announcement frames. At the end of thetransmission cycles for each announcement frame, in each of the antennasectors, a slot is assigned for SSW frame exchanges. In at least oneembodiment, a period of time is reserved for peer link establishment atthe end of the transmission of all cycles and SSW slots. At the time ofthe beacon transmission in the regular frame, if the new node isconnected to the mesh node a peer beacon and an assigned SSW slot isadded and dedicated to the new node with MSTA B.

FIG. 38A and FIG. 38B depict an example embodiment 1010 of the aboveprocess between MSTA A 1012, MSTA B 1014, MSTA C 1016. In FIG. 38A onesees the beacons 1030, 1032, 1034 with the ABFT and DTI periodspreceding an assisted discovery period 1018. In this assisted discoveryperiod announcement frames 1022, 1024, 1026 are seen between which areSSW frame exchange 1020, followed by a possible link setup slot 1028. InFIG. 38B beacons are sent 1036, 1038, 1040 followed by ABFT and DTIcommunications.

This technique will avoid any interruption to beacon master switchingprotocol used in the mesh network where it's not needed to switch thebeacon master to assist the new node in the protocol.

4.10. Simplified Efficient Beaconing Mode

In this section, a simple mode of operation is described. The mesh nodesare assigned the master beacon role in a periodic sequence. Each meshnode is assigned a time to start sending the discovery beacons, numberof beacons to serve as a beacon master (discovery period) and period torepeat its role (master beacon interval). A center entity or a mesh nodemight be responsible of managing this operation. Without a centerentity, some of this information can be defined also in the mesh profile(discovery period and the master beacon period). Mesh nodes can pick thetime to start its discovery period randomly from a predefined slot or bychannel sensing.

When a new node tries to join the mesh network, it can passively listenfor master beacon interval to receive all beacons transmitted in thedifferent discovery periods. A form of mesh assistance can be applied bycoordination between the mesh nodes after one mesh node discover the newnode. This is by scheduling nodes to send beacons in the DTI period aswas seen in FIG. 38A and FIG. 38B. Another form of assistance by forcingthe new node to transmit probe requests in all directions and forcingthe mesh nodes to listen for probe requests from the new node.

4.11 New Frame Format

4.11.1. Beacon Response

This frame is needed when a new node (STA) is using passive scanning anddiscovers a beacon. The new STA sends a beacon response to inform thediscovered STA about its existence. This frame can be used to triggerbeamforming training as well if needed. In at least one embodiment, theframe of an assistance request message contains the followinginformation: (a) NSID—indicating the new STA to be assisted; (b)SSID/SSID list—providing a list of SSIDs the new STA is trying toconnect to; (c) DMG capabilities—indicating new STA supportedcapabilities; (d) Mesh ID—mesh identification element; (e) AssistanceRequest flag—indicates if the new STA is requesting mesh discoveryassistance; (f) beamforming training request—indicating whether a newSTA is requesting beamforming training; (g) beacon ID—the MSTA discoverybeacon ID; (h) beam ID—transmit beam ID in case of directiontransmission of beacon response message; (i) message counter—messagecounter if frame is transmitted multiple times from Omni/quasi-Omniantenna.

4.11.2. Beacon Response ACK

This message frame is sent from the discovered MSTA to the new STA incase of passive scanning to confirm the reception of the beacon responsemessage and to setup the mesh discovery assistance phase. In at leastone embodiment, the frame of a beacon response ACK message contains thefollowing information: (a) assistance confirmation—providing a meshassistance confirmation; (b) new STA best transmit beam—indicating thebest transmit beam for the new STA if the new STA directionallytransmits the beacon response; (c) assistance information—assistancecoordination information.

4.11.3. Discovery Beacon

This is a frame that is similar to the regular 802.11 DMG beacons framesbut has some elements to allow for additional features. These frames aretransmitted by the beacon master in all directions to help in discoveryand announcing the network. This frame contains specific details for newnodes to discover the network and is different than the peer beaconswhich are intended to synchronize and manage mesh peers and connectedSTAs. Many elements of the 802.11 DMG beacon can be removed orconsidered optional if they are not needed by new node discovery. Oncethe node is connected to the mesh network, it can receive all theomitted information through peer beacons. This is a very light (lowoverhead) beacon and has the basic information for a node to discoverthe mesh node, form a connection and start receiving peer beacons. In atleast one embodiment, the frame of an assistance response messagecontains the following information: (a) beacon type—discovery or peerbeacon;

(b) current BM countdown timer—countdown timer to the next BM cycle.

4.11.4. Peer Beacon

This is a frame that is similar to the regular 802.11 DMG beacons framesbut has some elements to provide for additional features. These framesare transmitted by all nodes to their peer STAs in their respectivedirections or around their directions only. This beacon is used forbeacon functions like synchronization, spectrum and channel management.This information allows nodes in the network to manage the network andpropagate beacon master information. Many elements of the 802.11 DMGbeacon can be removed or considered optional if they are not needed bythe current mesh STA and are just meant for new nodes discovery and meshformation. In at least one embodiment, the frame of an assistanceresponse message contains the following information: (a) beacontype—discovery or peer beacon; (b) current BM ID—node ID of the currentbeacon master; (c) BM selection criterion—random or sequence based; (d)future BM ID or BM sequence—specifies next BM ID or the BM sequencenumber; (e) current BM countdown timer—countdown timer to the start ofthe next BM cycle; (f) extended beacon master information—if it has avalue it indicates more information is attached to the peer beacon toaid BM updates; (g) discovery period—the number of BIs that forms adiscovery period; (h) beacon master interval—number of BIs that form abeacon master interval. If extended beacon master information isdefined, the beacon contains some information element that is requiredto form some action.

4.11.4.1. New Node Announcement Message

This information element is used to inform the current beacon master ofthe existence of a new node that is found by some mesh node in thenetwork. The node that found the new node forms this element and othernodes forward it to the current BM. In at least one embodiment, theframe of an assistance response message contains the followinginformation: (a) new node ID—discovery or peer beacon; (b) discoverynode ID—node ID of the current beacon master; (c) discovery node sectorID—sector of the node which discovered the new node; and (d) new nodecapabilities—new node reported capabilities.

4.11.4.2. Beacon Master Temporary Schedule Update

This information element is used to interrupt and update the schedule ofthe beacon master. This can be used by the system if a new node isjoining the network and a discovery campaign is scheduled for it. In atleast one embodiment, the frame of an assistance response messagecontains the following information: (a) number of scheduled beaconmasters—number of beacon masters that are urgently scheduled to help thenew node; (b) new node ID—node ID of the new node to be assisted; (c) BM1, BM 2, BM 3, . . . — a list of node IDs of scheduled nodes to serve asbeacon masters.

4.11.4.3. Registration Request

This is to inform the current beacon master that a new node requests toregister as future beacon master. A node might also decide not to serveas a beacon master for some time and then switch to enable the beaconmaster option. This request flag allows other nodes to schedule thisnode for future discovery cycles. In at least one embodiment, the frameof an assistance response message contains the following information:node ID—ID of the node that needs to register as a future BM.

4.11.4.4. Beacon Master Schedule Update

This is to inform nodes in the network about a new update in the steadystate beacon master switching updates. This can be in the form of addinga new node or removing a node from the current node list or currentsequence. In at least one embodiment, the beacon master schedule updateincludes the following fields: (a) number of nodes to update—number ofthe beacon masters that added or removed from the list or sequence; (b)new nodes IDs—node IDs for the nodes to be added or removed from thenode list or sequence; (c) action—add or remove nodes; and (d) newsequence—new updated sequence for the list after adding or removing thenew nodes.

5. Summary

Wireless communication system/apparatus/method with directionaltransmission performing transmission of signals that aid scanning formesh network discovery and maintenance of links among peer STAs in themesh network, comprising: (a) STA transmits first type of beacons tomaintain existing links among one or more neighboring peer STA(s) inwhich (a)(i) first type of beacons contain time synchronization andresource management information; (a)(ii) STA transmits the first type ofbeacons with reduced number of antenna sectors; (b) STA transmits secondtype of beacons to aid network discovery for newly joining STAs, inwhich (b)(i) the second type of beacons contain mesh network profileinformation which is used for the identification of the operatingnetwork; (b)(ii) STA transmits the second type of beacons withcoordination among other STAs in the network.

In addition to the above, in at least one embodiment, an STA that issearching for an available network nearby performs either activescanning or passive scanning, the STA transmits a signal to notify theintent of the network discovery.

In addition to the above, in at least one embodiment, upon reception ofthe signal notifying the intent of the network discovery, one STA ormore in the existing network schedules transmission of discovery beaconstoward the STA searching for an available network.

In addition to the above, in at least one embodiment, an STA thatreceived said signal notifying the intent of the network discoverytransmits a subset of the received information to a scheduling entity ofthe network, the scheduling entity of the network collects informationfrom STAs in the network, determines the transmission time andtransmitting STA(s) of the discovery beacon, and notifies thetransmitting STA(s) of the transmission time of the discovery beacon.

In addition to the above, in at least one embodiment, STA that receivedsaid transmission time of the discovery transmits discovery beacons asinstructed by the received information.

In addition to the above, in at least one embodiment, STA collectsinformation about the newly joining STA from its neighboring peer STAs,and determines the timing of the transmission of discovery beacons, andtransmits discovery beacons as determined.

In addition to the above, in at least one embodiment, Mesh STAs cancoordinate the transmission of network announcement frames in alldirections to the new node during the data transmission period to assistin quick neighbor discovery.

The enhancements described in the presented technology can be readilyimplemented within various mmWave transmitters, receivers andtransceivers. It should also be appreciated that modern transmitters,receivers and transceivers are preferably implemented to include one ormore computer processor devices (e.g., CPU, microprocessor,microcontroller, computer enabled ASIC, etc.) and associated memorystoring instructions (e.g., RAM, DRAM, NVRAM, FLASH, computer readablemedia, etc.) whereby programming (instructions) stored in the memory areexecuted on the processor to perform the steps of the various processmethods described herein.

The computer and memory devices were not depicted in the diagrams forthe sake of simplicity of illustration, as one of ordinary skill in theart recognizes the use of computer devices for carrying out stepsinvolved with various modern communication devices. The presentedtechnology is non-limiting with regard to memory and computer-readablemedia, insofar as these are non-transitory, and thus not constituting atransitory electronic signal.

It will also be appreciated that the computer readable media (memorystoring instructions) in these computational systems is“non-transitory”, which comprises any and all forms of computer-readablemedia, with the sole exception being a transitory, propagating signal.Accordingly, the disclosed technology may comprise any form ofcomputer-readable media, including those which are random access (e.g.,RAM), require periodic refreshing (e.g., DRAM), those that degrade overtime (e.g., EEPROMS, disk media), or that store data for only shortperiods of time and/or only in the presence of power, with the onlylimitation being that the term “computer readable media” is notapplicable to an electronic signal which is transitory.

Embodiments of the present technology may be described herein withreference to flowchart illustrations of methods and systems according toembodiments of the technology, and/or procedures, algorithms, steps,operations, formulae, or other computational depictions, which may alsobe implemented as computer program products. In this regard, each blockor step of a flowchart, and combinations of blocks (and/or steps) in aflowchart, as well as any procedure, algorithm, step, operation,formula, or computational depiction can be implemented by various means,such as hardware, firmware, and/or software including one or morecomputer program instructions embodied in computer-readable programcode. As will be appreciated, any such computer program instructions maybe executed by one or more computer processors, including withoutlimitation a general purpose computer or special purpose computer, orother programmable processing apparatus to produce a machine, such thatthe computer program instructions which execute on the computerprocessor(s) or other programmable processing apparatus create means forimplementing the function(s) specified.

Accordingly, blocks of the flowcharts, and procedures, algorithms,steps, operations, formulae, or computational depictions describedherein support combinations of means for performing the specifiedfunction(s), combinations of steps for performing the specifiedfunction(s), and computer program instructions, such as embodied incomputer-readable program code logic means, for performing the specifiedfunction(s). It will also be understood that each block of the flowchartillustrations, as well as any procedures, algorithms, steps, operations,formulae, or computational depictions and combinations thereof describedherein, can be implemented by special purpose hardware-based computersystems which perform the specified function(s) or step(s), orcombinations of special purpose hardware and computer-readable programcode.

Furthermore, these computer program instructions, such as embodied incomputer-readable program code, may also be stored in one or morecomputer-readable memory or memory devices that can direct a computerprocessor or other programmable processing apparatus to function in aparticular manner, such that the instructions stored in thecomputer-readable memory or memory devices produce an article ofmanufacture including instruction means which implement the functionspecified in the block(s) of the flowchart(s). The computer programinstructions may also be executed by a computer processor or otherprogrammable processing apparatus to cause a series of operational stepsto be performed on the computer processor or other programmableprocessing apparatus to produce a computer-implemented process such thatthe instructions which execute on the computer processor or otherprogrammable processing apparatus provide steps for implementing thefunctions specified in the block(s) of the flowchart(s), procedure (s)algorithm(s), step(s), operation(s), formula(e), or computationaldepiction(s).

It will further be appreciated that the terms “programming” or “programexecutable” as used herein refer to one or more instructions that can beexecuted by one or more computer processors to perform one or morefunctions as described herein. The instructions can be embodied insoftware, in firmware, or in a combination of software and firmware. Theinstructions can be stored local to the device in non-transitory media,or can be stored remotely such as on a server, or all or a portion ofthe instructions can be stored locally and remotely. Instructions storedremotely can be downloaded (pushed) to the device by user initiation, orautomatically based on one or more factors.

It will further be appreciated that as used herein, that the termsprocessor, hardware processor, computer processor, central processingunit (CPU), and computer are used synonymously to denote a devicecapable of executing the instructions and communicating withinput/output interfaces and/or peripheral devices, and that the termsprocessor, hardware processor, computer processor, CPU, and computer areintended to encompass single or multiple devices, single core andmulticore devices, and variations thereof.

From the description herein, it will be appreciated that the presentdisclosure encompasses multiple embodiments which include, but are notlimited to, the following:

1. An apparatus for wireless communication in a mesh network, theapparatus comprising: (a) a wireless communication circuit configuredfor wirelessly communicating with other wireless communication stationsutilizing directional transmission having a plurality of antenna patternsectors each having different transmission directions; (b) a processorcoupled to said wireless communication circuit; and (c) a non-transitorymemory storing instructions executable by the processor; (d) whereinsaid instructions, when executed by the processor, perform stepscomprising: (d)(i) transmitting a first type of beacon, a peer beacon,comprising time synchronization and resource management information, tomaintain existing links among one or more neighboring peer stationswithin the mesh network; and (d)(ii) transmitting a second type ofbeacon, a network discovery beacon, containing mesh network profileinformation which identifies said mesh network, to aid network discoveryfor wireless communication stations to join said mesh network.

2. An apparatus for wireless communication in a mesh network, theapparatus comprising: (a) a wireless communication circuit configuredfor wirelessly communicating with other wireless communication stationsutilizing directional transmission having a plurality of antenna patternsectors each having different transmission directions; (b) wherein saiddirectional transmission aids scanning for mesh network discovery andmaintenance of links among peer stations in said mesh network; (c) aprocessor coupled to said wireless communication circuit; and (d) anon-transitory memory storing instructions executable by the processor;(e) wherein said instructions, when executed by the processor, performsteps comprising: (e) (i) transmitting a first type of beacon, a peerbeacon, comprising time synchronization and resource managementinformation, to maintain existing links among one or more neighboringpeer stations within the mesh network; in which said first type ofbeacon is transmitted to a reduced number of antenna sector directions,from said plurality of antenna pattern sectors, based on peer locations;and (e)(ii) transmitting a second type of beacon, a network discoverybeacon, containing mesh network profile information which identifiessaid mesh network, to aid network discovery for wireless communicationstations to join said mesh network, in which said second type of beaconis transmitted after coordination among stations in said mesh network sothat not all stations are required to send said second type of beacon.

3. A method of wireless communication in a mesh network, the methodcomprising: (a) transmitting a first type of beacon, a peer beacon,comprising time synchronization and resource management information, tomaintain existing links among one or more neighboring peer stationswithin a mesh network of wireless communication stations which utilizedirectional transmission having a plurality of antenna pattern sectorseach having different transmission directions; and (b) transmitting asecond type of beacon, a network discovery beacon, containing meshnetwork profile information which identifies said mesh network, to aidnetwork discovery for wireless communication stations to join said meshnetwork.

4. The apparatus or method of any preceding embodiment, wherein saiddirectional transmission aids scanning for mesh network discovery andmaintenance of links among peer stations in said mesh network.

5. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor perform transmitting of saidfirst type of beacon to a reduced number of antenna sector directions,from said plurality of antenna pattern sectors, based on peer locations.

6. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor perform transmitting of saidsecond type of beacon utilizing coordination among stations in said meshnetwork, whereby not all stations are required to send said second typeof beacon.

7. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor further perform stepscomprising searching for an available network nearby utilizing eitheractive scanning or passive scanning, and responding to receiving saidnetwork discovery beacon by transmitting a signal to notify the intentof joining said mesh network.

8. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor further perform stepscomprising transmitting a signal notifying intent to join the meshnetwork, wherein at least one station in said mesh network receivingsaid signal notifying intent to join the mesh network schedulestransmission of discovery beacons toward the station searching to jointhe mesh network.

9. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor further perform stepscomprising transmitting a subset of information received from thestation sending said signal notifying intent to join the mesh network toa scheduling entity of the mesh network, wherein said scheduling entityof the mesh network collects information from stations in the network,determines the transmission time and at least one transmitting stationto generate said discovery beacon, and transmits notifications to thesestations of transmission time for said discovery beacon.

10. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor further perform stepscomprising transmitting discovery beacons in response to instructions totransmit discovery beacons at said transmission time as received fromsaid scheduling entity of the mesh network.

11. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor further perform stepscomprising collecting information about a station newly joining the meshnetwork from its neighboring peer stations, determining timing oftransmission of discovery beacons, and transmitting discovery beacons atthe determined timing.

12. The apparatus or method of any preceding embodiment, wherein saidinstructions when executed by the processor further perform stepscomprising coordinating transmission of network announcement framesbetween stations in said mesh network, wherein in response to saidcoordination at least one of said stations in the mesh network transmitssaid network announcement frames in all directions to a new node duringa data transmission period to assist in neighbor discovery.

13. The apparatus or method of any preceding embodiment, furthercomprising transmitting of said peer beacon to a reduced number ofantenna sector directions, from said plurality of antenna patternsectors, based on peer locations.

14. The apparatus or method of any preceding embodiment, furthercomprising transmitting of said discovery beacon utilizing coordinationamong stations in said mesh network, whereby not all stations arerequired to send said discovery beacon.

As used herein, the singular terms “a,” “an,” and “the” may includeplural referents unless the context clearly dictates otherwise.Reference to an object in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”

As used herein, the term “set” refers to a collection of one or moreobjects. Thus, for example, a set of objects can include a single objector multiple objects.

As used herein, the terms “substantially” and “about” are used todescribe and account for small variations. When used in conjunction withan event or circumstance, the terms can refer to instances in which theevent or circumstance occurs precisely as well as instances in which theevent or circumstance occurs to a close approximation. When used inconjunction with a numerical value, the terms can refer to a range ofvariation of less than or equal to ±10% of that numerical value, such asless than or equal to ±5%, less than or equal to ±4%, less than or equalto ±3%, less than or equal to ±2%, less than or equal to ±1%, less thanor equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to±0.05%. For example, “substantially” aligned can refer to a range ofangular variation of less than or equal to ±10°, such as less than orequal to ±5°, less than or equal to ±4°, less than or equal to ±3°, lessthan or equal to ±2°, less than or equal to ±1°, less than or equal to±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°.

Additionally, amounts, ratios, and other numerical values may sometimesbe presented herein in a range format. It is to be understood that suchrange format is used for convenience and brevity and should beunderstood flexibly to include numerical values explicitly specified aslimits of a range, but also to include all individual numerical valuesor sub-ranges encompassed within that range as if each numerical valueand sub-range is explicitly specified. For example, a ratio in the rangeof about 1 to about 200 should be understood to include the explicitlyrecited limits of about 1 and about 200, but also to include individualratios such as about 2, about 3, and about 4, and sub-ranges such asabout 10 to about 50, about 20 to about 100, and so forth.

Although the description herein contains many details, these should notbe construed as limiting the scope of the disclosure but as merelyproviding illustrations of some of the presently preferred embodiments.Therefore, it will be appreciated that the scope of the disclosure fullyencompasses other embodiments which may become obvious to those skilledin the art.

All structural and functional equivalents to the elements of thedisclosed embodiments that are known to those of ordinary skill in theart are expressly incorporated herein by reference and are intended tobe encompassed by the present claims. Furthermore, no element,component, or method step in the present disclosure is intended to bededicated to the public regardless of whether the element, component, ormethod step is explicitly recited in the claims. No claim element hereinis to be construed as a “means plus function” element unless the elementis expressly recited using the phrase “means for”. No claim elementherein is to be construed as a “step plus function” element unless theelement is expressly recited using the phrase “step for”.

TABLE 1 Discovery Zone Formation Exemplified in FIG. 33 List L₁ L₂ L₃ L₄L₅ L₆ Neighbor list A-S4 A-S4, C-S1 C-S1 C-S1, A-S3 C-S1, B-S4, A-S3B-S4, A-S3 Discovery A-S4 = { } A-S4 = {C-S1} A-S4 = {C-S1} A-S4 ={C-S1} A-S4 = {C-S1} A-S4 = {C-S1} zone update A-S3 = { } A-S3 = { }A-S3= { } A-S3= {C-S1} A-S3 = {C-S1, B-S4} A-S3 = {C- C-S1 = { } C-S1 ={A-S4} C-S1 = {A-S4} C-S1 = {A-S4, C-S1 = {A-S4, A- S1, B-S4} B-S4 = { }B-S4 = { } B-S4 = { } A-S3} S3, B-S4} C-S1 = {A-S4, B-S4= { } B-S4 ={C-S1, A-S3} A-S3, B-S4} B-S4 = {C- S1, A-S3}

What is claimed is:
 1. An apparatus for wireless communication in a meshnetwork, the apparatus comprising: (a) a wireless communication circuitconfigured as a station for wirelessly communicating with other wirelesscommunication stations in a mesh network utilizing directionaltransmission having a plurality of antenna pattern sectors each havingdifferent transmission directions; (b) a processor coupled to saidwireless communication circuit; and (c) a non-transitory memory storinginstructions executable by the processor; (d) wherein said instructions,when executed by the processor operating as a station performing as abeacon master (BM), perform steps comprising: (i) transmitting a firsttype of beacon, a network discovery beacon, containing mesh networkprofile information which identifies said mesh network, to aid networkdiscovery for wireless communication stations to join said mesh network,with said beacon master being an only station allowed to transmit saidnetwork discovery beacons on said mesh network; and (ii) wherein onlysaid beacon master (BM) also performs (A) receiving and processing newbeacon master (BM) requests; (B) scheduling a new beacon master (BM)schedule based on received beacon master (BM) requests; (C) updating asteady-state beacon master (BM) sequence; (D) defining scanning receivedirections for a new station joining said mesh network; (E) updatingdiscovery beacon scanning directions for peer stations of a new nodejoining said mesh network; (iii) transmitting a second type of beacon, apeer beacon, comprising time synchronization and resource managementinformation, to maintain existing links among one or more neighboringpeer stations within said mesh network; in which said second type ofbeacon is transmitted to a reduced number of antenna sector directions,from said plurality of antenna pattern sectors, based on peer locations,with said beacon master being only one of the stations in said meshnetwork allowed to transmit said peer beacons; and (iv) wherein activestations in said mesh network become a beacon master (BM) according to aselected sequence, with the sequence remaining valid until a new stationbecomes discoverable by an existing station of the mesh network.
 2. Theapparatus of claim 1, wherein said directional transmission aidsscanning for mesh network discovery and maintenance of links among peerstations in said mesh network.
 3. The apparatus of claim 1, wherein saidinstructions when executed by the processor perform transmitting of saidfirst type of beacon to a reduced number of antenna sector directions,from said plurality of antenna pattern sectors, based on peer locations.4. The apparatus of claim 1, wherein said instructions when executed bythe processor perform transmitting of said second type of beaconutilizing coordination among stations in said mesh network, whereby notall stations are required to send said second type of beacon.
 5. Theapparatus of claim 1, wherein said instructions when executed by theprocessor when operating as a new station attempting to join the meshnetwork, further perform steps comprising searching for an availablenetwork nearby utilizing either active scanning or passive scanning, andresponding to receiving said network discovery beacon by transmitting asignal to notify the intent of joining said mesh network.
 6. Theapparatus of claim 1, wherein said instructions when executed by theprocessor when operating as a new station attempting to join the meshnetwork, further perform steps comprising transmitting a signalnotifying intent to join the mesh network, wherein at least one stationin said mesh network receiving said signal notifying intent to join themesh network schedules transmission of discovery beacons toward thestation searching to join the mesh network.
 7. The apparatus of claim 6,wherein said instructions when executed by the processor when operatingas a new station attempting to join the mesh network, further performsteps comprising transmitting a subset of information received from thestation sending said signal notifying intent to join the mesh network toa scheduling entity of the mesh network, wherein said scheduling entityof the mesh network collects information from stations in the network,determines the transmission time and at least one transmitting stationto generate said discovery beacon, and transmits notifications to thesestations of transmission time for said discovery beacon.
 8. Theapparatus of claim 7, wherein said instructions when executed by theprocessor further perform steps comprising transmitting discoverybeacons in response to instructions to transmit discovery beacons atsaid transmission time as received from said scheduling entity of themesh network.
 9. The apparatus of claim 1, wherein said instructionswhen executed by the processor further perform steps comprisingcollecting information about a station newly joining the mesh networkfrom its neighboring peer stations, determining timing of transmissionof discovery beacons, and transmitting discovery beacons at thedetermined timing.
 10. The apparatus of claim 1, wherein saidinstructions when executed by the processor further perform stepscomprising coordinating transmission of network announcement framesbetween stations in said mesh network, wherein in response to saidcoordination at least one of said stations in the mesh network transmitssaid network announcement frames in all directions to a new node duringa data transmission period to assist in neighbor discovery.
 11. Anapparatus for wireless communication in a mesh network, the apparatuscomprising: (a) a wireless communication circuit configured as a stationfor wirelessly communicating with other wireless communication stationsin a mesh network utilizing directional transmission having a pluralityof antenna pattern sectors each having different transmissiondirections; (b) wherein said directional transmission aids scanning formesh network discovery and maintenance of links among peer stations insaid mesh network; (c) a processor coupled to said wirelesscommunication circuit; and (d) a non-transitory memory storinginstructions executable by the processor; (e) wherein said instructions,when executed by the processor operating as a station performing as abeacon master (BM), perform steps comprising: (i) transmitting a firsttype of beacon, a network discovery beacon, containing mesh networkprofile information which identifies said mesh network, to aid networkdiscovery for wireless communication stations to join said mesh network,in which said first type of beacon is transmitted after coordinationamong stations in said mesh network so that not all stations arerequired to send said second type of beacon, with said beacon masterbeing an only station allowed to transmit said network discovery beaconson said mesh network; (ii) wherein only said beacon master (BM) alsoperforms (A) receiving and processing new beacon master (BM) requests;(B) scheduling a new beacon master (BM) schedule based on receivedbeacon master (BM) requests; (C) updating a steady-state beacon master(BM) sequence; (D) defining scanning receive directions for a newstation joining the mesh network; (E) updating discovery beacon scanningdirections for peer stations of a new node joining the mesh network;(iii) transmitting a second type of beacon, a peer beacon, comprisingtime synchronization and resource management information, to maintainexisting links among one or more neighboring peer stations within themesh network, with said beacon master being only one of the stations inthe mesh network allowed to transmit said peer beacons; and (iv) whereinactive stations in the mesh network become a beacon master (BM)according to a selected sequence, with the sequence remaining validuntil a new station becomes discoverable by an existing station of themesh network.
 12. The apparatus of claim 11, wherein said instructionswhen executed by the processor when operating as a new stationattempting to join the mesh network, further perform steps comprisingsearching for an available network nearby utilizing either activescanning or passive scanning, and responding to receiving said networkdiscovery beacon by transmitting a signal to notify the intent ofjoining said mesh network.
 13. The apparatus of claim 11, wherein saidinstructions when executed by the processor when operating as a newstation attempting to join the mesh network, further perform stepscomprising transmitting a signal notifying intent to join the meshnetwork, wherein at least one station in said mesh network receivingsaid signal notifying intent to join the mesh network schedulestransmission of discovery beacons toward the station searching to jointhe mesh network.
 14. The apparatus of claim 13, wherein saidinstructions when executed by the processor when operating as a newstation attempting to join the network, further perform steps comprisingtransmitting a subset of information received from the station sendingsaid signal notifying intent to join the mesh network to a schedulingentity of the mesh network, wherein said scheduling entity of the meshnetwork collects information from stations in the network, determinesthe transmission time and at least one transmitting station to generatesaid discovery beacon, and transmits notifications to these stations oftransmission time for said discovery beacon.
 15. The apparatus of claim14, wherein said instructions when executed by the processor furtherperform steps comprising transmitting discovery beacons in response toinstructions to transmit discovery beacons at said transmission time asreceived from said scheduling entity of the mesh network.
 16. Theapparatus of claim 11, wherein said instructions when executed by theprocessor further perform steps comprising collecting information abouta station newly joining the mesh network from its neighboring peerstations, determining timing of transmission of discovery beacons, andtransmitting discovery beacons at the determined timing.
 17. Theapparatus of claim 11, wherein said instructions when executed by theprocessor further perform steps comprising coordinating transmission ofnetwork announcement frames between stations in said mesh network,wherein in response to said coordination at least one of said stationsin the mesh network transmits said network announcement frames in alldirections to a new node during a data transmission period to assist inneighbor discovery.
 18. A method of wireless communication in a meshnetwork, the method comprising: (a) operating as a station performing asa beacon master (BM) in transmitting a first type of beacon, a networkdiscovery beacon, containing mesh network profile information whichidentifies a mesh network, to aid network discovery for wirelesscommunication stations to join said mesh network, with said beaconmaster being an only station allowed to transmit said network discoverybeacons; (b) wherein only said beacon master (BM) also performs (A)receiving and processing new beacon master (BM) requests; (B) schedulinga new beacon master (BM) schedule based on received beacon master (BM)requests; (C) updating a steady-state beacon master (BM) sequence; (D)defining scanning receive directions for a new station joining the meshnetwork; (E) updating discovery beacon scanning directions for peerstations of a new station joining the mesh network; (c) transmitting asecond type of beacon, a peer beacon, comprising time synchronizationand resource management information, to maintain existing links amongone or more neighboring peer stations within a mesh network of wirelesscommunication stations which utilize directional transmission having aplurality of antenna pattern sectors each having different transmissiondirections, with said beacon master being only one of the stations inthe mesh network allowed to transmit said peer beacons; and (d) whereinactive stations in the mesh network become a beacon master (BM)according to a selected sequence, with the sequence remaining validuntil a new station becomes discoverable by an existing station of themesh network.
 19. The method of claim 18, further comprisingtransmitting of said peer beacon to a reduced number of antenna sectordirections, from said plurality of antenna pattern sectors, based onpeer locations.
 20. The method of claim 18, further comprisingtransmitting of said discovery beacon utilizing coordination amongstations in said mesh network, whereby not all stations are required tosend said discovery beacon.